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 A004797 #24 Jan 05 2025 19:51:33 %S A004797 1,4,8,14,22,30,41,54,67,82,99,118,138,160,182,206,234,262,292,322, %T A004797 353,388,425,462,501,542,583,626,671,718,766,818,870,922,976,1030, %U A004797 1088,1148,1210,1274,1338,1402,1469,1538,1607,1678,1753,1828,1905,1984,2063 %N A004797 Convolution of A002024 with itself. %H A004797 Robert Israel, <a href="/A004797/b004797.txt">Table of n, a(n) for n = 0..10000</a> %H A004797 Raphael Schumacher, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Papers1/55-2/Schumacher12132016.pdf">The self-counting identity</a>, Fib. Quart., 55 (No. 2 2017), 157-167. %F A004797 G.f.: (1/(1 - x)^2)*Product_{k>=1} (1 - x^(2*k))^2/(1 - x^(2*k-1))^2. - _Ilya Gutkovskiy_, May 30 2017 %p A004797 a002024:= [seq(i$i,i=1..10)]: %p A004797 g002024:= add(a002024[i]*x^(i-1),i=1..nops(a002024)): %p A004797 g:= expand(g002024^2): %p A004797 seq(coeff(g,x,i),i=0..degree(g002024)); # _Robert Israel_, May 30 2017 %o A004797 (PARI) nn(n)=(sqrtint(n*8)+1)\2; %o A004797 a(n) = sum(k=1, n, nn(k)*nn(n-k+1)); \\ _Michel Marcus_, May 30 2017 %Y A004797 Cf. A002024. %K A004797 nonn %O A004797 0,2 %A A004797 _N. J. A. Sloane_