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 A124458 #5 Dec 29 2023 11:55:30 %S A124458 1,2,1,3,2,1,3,4,2,1,3,5,5,2,1,3,7,7,6,2,1,3,8,12,9,7,2,1,3,10,15,18, %T A124458 11,8,2,1,3,11,22,24,25,13,9,2,1,3,13,26,40,35,33,15,10,2,1 %N A124458 Triangular array resulting from summing three repeated Pascal sequences; related to the generalized pentagonal sequence (A001318) and the classical modular tessellation (cf. A054886). %C A124458 The third diagonal is the generalized pentagonal sequence A001318 %e A124458 Consider %e A124458 1.......1.......6.......6.......21......21.... %e A124458 ........1.......1.......6.......6.......21.... %e A124458 ................1.......1.......6.......6..... %e A124458 which sums to %e A124458 1.....2....8.....13....33....48...., %e A124458 a diagonal of A124458 %Y A124458 Cf. A000012 A004526 A001651 A008805 A001318 A058187 A028724 A093039 A054886 (row sum). %K A124458 easy,nonn,tabl %O A124458 1,2 %A A124458 _Alford Arnold_, Nov 04 2006