Updated answer
The field for these sort of jobs in the biblatex standard data model is called eid. (Up to and including version 3.14 of biblatex the field is only available for @articles, but from v3.15 onwards it will be supported by all types where it makes sense, see https://github.com/plk/biblatex/pull/1000).
If you don't like the default output, you can modify it to show "Art. No.".
\documentclass{article}
\usepackage[backend=biber, style=authoryear]{biblatex}
\NewBibliographyString{artno}
\DefineBibliographyStrings{english}{artno = {Art\adddotspace No\adddot}}
\DeclareFieldFormat[article,periodical]{eid}{\bibstring{artno}\addabbrvspace #1}
\begin{filecontents*}{\jobname.bib}
@article{mooney,
author = {Mooney, Carl H. and Roddick, John F.},
title = {Sequential Pattern Mining -- Approaches and Algorithms},
journal = {ACM Comput. Surv.},
volume = {45},
number = {2},
date = {2013-03},
pages = {19:1--19:39},
eid = {19},
pagetotal = {39},
doi = {10.1145/2431211.2431218},
}
\end{filecontents*}
\addbibresource{\jobname.bib}
\begin{document}
\cite{mooney}
\printbibliography
\end{document}
Old answer
If for some reason you don't want to use eid you can define a new articleno field.
This is done in a separate .dbx file called articleno.dbx (in the MWE it is created via filecontents)
\ProvidesFile{articleno.dbx}
\DeclareDatamodelFields[type=field,datatype=integer]{articleno}
\DeclareDatamodelEntryfields[article]{articleno}
We can also define a new bibstring to be printed before the article number
\NewBibliographyString{artno}
\DefineBibliographyStrings{english}{artno = {Art\adddotspace No\adddot}}
The articleno field is introduced by this new string
\DeclareFieldFormat{articleno}{\bibstring{artno}\addabbrvspace #1}
We then redefine the note+pages macro to also print the articleno field
\renewbibmacro*{note+pages}{%
\printfield{note}%
\setunit{\bibpagespunct}%
\printfield{articleno}
\setunit{\bibpagespunct}%
\printfield{pages}%
\newunit}
MWE
\documentclass{article}
\usepackage[backend=biber,style=authoryear,datamodel=articleno]{biblatex}
\begin{filecontents*}{\jobname.bib}
@article{mooney,
author = {Mooney, Carl H. and Roddick, John F.},
title = {Sequential Pattern Mining -- Approaches and Algorithms},
journal = {ACM Comput. Surv.},
volume = {45},
number = {2},
date = {2013-03},
pages = {19:1--19:39},
articleno = {19},
pagetotal = {39},
doi = {10.1145/2431211.2431218},
}
\end{filecontents*}
\begin{filecontents*}{articleno.dbx}
\ProvidesFile{articleno.dbx}
\DeclareDatamodelFields[type=field,datatype=integer]{articleno}
\DeclareDatamodelEntryfields[article]{articleno}
\end{filecontents*}
\NewBibliographyString{artno}
\DefineBibliographyStrings{english}{artno = {Art\adddotspace No\adddot}}
\DeclareFieldFormat{articleno}{\bibstring{artno}\addabbrvspace #1}
\renewbibmacro*{note+pages}{%
\printfield{note}%
\setunit{\bibpagespunct}%
\printfield{articleno}
\setunit{\bibpagespunct}%
\printfield{pages}%
\newunit}
\addbibresource{\jobname.bib}
\begin{document}
\cite{mooney}
\printbibliography
\end{document}

notefield. – Bernard Aug 01 '14 at 20:49pages = {19:1--19:39}, articleno = {19}when clicking on he citation button. Instead, we seearticleno = {19}, numpages = {39}. – Feb 23 '23 at 19:16