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 A096901 #16 Mar 03 2024 03:56:38 %S A096901 1,0,1,1,0,1,1,1,2,4,3,9,14,13,52,124,161,181,715,2338,7073,8624, %T A096901 15466,52858,150365,316543,691771,1681604,5324919,15407311,37417775, %U A096901 69725286,155786456,579599171,2600274145,10530031625,22971756045,47057778714,112946192928 %N A096901 Number of permutations p of (1,2,3,...,n) such that k+p(k) is a triangular number for 1<=k<=n. %F A096901 a(n) = permanent(m), where the n X n matrix m is defined by m(i,j) = 1 or 0, depending on whether i+j is a triangular number or not. %Y A096901 Cf. A006063, A073364, A095986, A097082, A097083, A096680. %Y A096901 See also A000217. %K A096901 nonn %O A096901 0,9 %A A096901 _Ray Chandler_, Jul 26 2004 %E A096901 More terms from _David Wasserman_, Nov 27 2007 %E A096901 a(0) and a(31)-a(38) from _Martin Ehrenstein_, Mar 03 2024