This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A371481 #5 Mar 26 2024 11:14:17
%S A371481 1,1,3,15,52,335,2031,12880,102614,802443,6956995,64721756,633754320,
%T A371481 6551212057,71375943289,820250162880,9747543483676,121775559807881,
%U A371481 1580353806494781,21246545374234378,296590230821338520,4280692741624646151,63852747607056438283
%N A371481 Expansion of e.g.f. Product_{k>=1} (1 + x^k/k!)^(k*(k+1)/2).
%C A371481 "EGJ" (unordered, element, labeled) transform of triangular numbers.
%H A371481 C. G. Bower, <a href="/transforms2.html">Transforms (2)</a>
%t A371481 nmax = 22; CoefficientList[Series[Product[(1 + x^k/k!)^(k (k + 1)/2), {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]!
%Y A371481 Cf. A000217, A007837, A028377, A032315, A032316, A371309.
%K A371481 nonn
%O A371481 0,3
%A A371481 _Ilya Gutkovskiy_, Mar 25 2024