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 A320963 #14 Jan 05 2024 13:38:03 %S A320963 1,1,2,3,6,15,51,227,1257,8296,63394,549740,5330185,57117590, %T A320963 670163058,8543228103,117564576721,1736762231296,27411856376831, %U A320963 460320540171210,8194312180092795,154127845115561811,3054239953905841713,63597989583700047353,1388275729125313815336 %N A320963 a(n) = Sum_{j=0..n} Sum_{k=0..j} abs( Stirling1(j - k, k) ). %H A320963 Andrew Howroyd, <a href="/A320963/b320963.txt">Table of n, a(n) for n = 0..200</a> %p A320963 a := n -> add(add(abs(Stirling1(j - k, k)), k=0..j), j=0..n): %p A320963 seq(a(n), n=0..29); %t A320963 a[n_] := Sum[Sum[Abs[StirlingS1[j - k, k]], {k, 0, j}], {j, 0, n}]; %t A320963 Array[a, 25, 0] (* _Amiram Eldar_, Nov 06 2018 *) %o A320963 (PARI) a(n)={sum(j=0, n, sum(k=0, j, abs(stirling(j-k, k, 1))))} \\ _Andrew Howroyd_, Nov 06 2018 %Y A320963 The Stirling_2 counterpart: A320964. %K A320963 nonn %O A320963 0,3 %A A320963 _Peter Luschny_, Nov 06 2018