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 A152204 #24 Oct 04 2024 20:48:32 %S A152204 1,3,5,1,7,3,9,5,1,11,7,3,13,9,5,1,15,11,7,3,17,13,9,5,1,19,15,11,7,3, %T A152204 21,17,13,9,5,1,23,19,15,11,7,3,25,21,17,13,9,5,1,27,23,19,15,11,7,3, %U A152204 29,25,21,17,13,9,5,1,31,27,23,19,15,11,7,3,33 %N A152204 Triangle read by rows: T(n,k) = 2*n-4*k+5 (n >= 0, 1 <= k <= 1+floor(n/2)). %C A152204 All terms are odd, decreasing across rows. Row sums = A000217, the triangular numbers. %C A152204 From _Johannes W. Meijer_, Sep 08 2013: (Start) %C A152204 Triangle read by rows formed from the antidiagonals of triangle A099375. %C A152204 The alternating row sums equal A098181(n). (End) %H A152204 Nathaniel Johnston, <a href="/A152204/b152204.txt">Rows n = 0..200 of irregular triangle, flattened</a> %F A152204 By columns, odd terms in every column, n-th column starts at row (2*n). %F A152204 From _Johannes W. Meijer_, Sep 08 2013: (Start) %F A152204 T(n, k) = A099375(n-k+1, k-1), n >= 0 and 1 <= k <= 1+floor(n/2). %F A152204 T(n, k) = A158405(n+1, n-2*k+2). (End) %e A152204 First few rows of the triangle: %e A152204 1 %e A152204 3 %e A152204 5 1 %e A152204 7 3 %e A152204 9 5 1 %e A152204 11 7 3 %e A152204 13 9 5 1 %e A152204 15 11 7 3 %e A152204 17 13 9 5 1 %e A152204 19 15 11 7 3 %e A152204 21 17 13 9 5 1 %e A152204 ... %p A152204 T := proc(n,k) return 2*n-4*k+5: end: seq(seq(T(n,k), k=1..1+floor(n/2)), n=0..20); # _Nathaniel Johnston_, May 01 2011 %Y A152204 Cf. A000217. %K A152204 nonn,tabf,easy %O A152204 0,2 %A A152204 _Gary W. Adamson_, Nov 29 2008 %E A152204 Edited by _N. J. A. Sloane_, Sep 25 2010, following a suggestion from Emeric Deutsch %E A152204 Offset corrected by _Johannes W. Meijer_, Sep 07 2013