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 A094615 #37 Mar 23 2021 21:21:07 %S A094615 1,3,5,7,11,17,15,23,35,53,31,47,71,107,161,63,95,143,215,323,485,127, %T A094615 191,287,431,647,971,1457,255,383,575,863,1295,1943,2915,4373,511,767, %U A094615 1151,1727,2591,3887,5831,8747,13121,1023,1535,2303,3455,5183,7775,11663,17495,26243,39365 %N A094615 Triangular array T of numbers generated by these rules: 1 is in T; and if x is in T, then 2x+1 and 3x+2 are in T. %C A094615 To obtain row n from row n-1, apply 2x+1 to each x in row n-1 and then put -1+2*3^n at the end. Or, instead, apply 3x+2 to each x in row n-1 and then put -1+2^(n+1) at the beginning. %C A094615 Subtriangle of the triangle in A230445. - _Philippe Deléham_, Oct 31 2013 %H A094615 Michel Marcus, <a href="/A094615/b094615.txt">Rows n=0..99 of triangle, flattened</a> %F A094615 T(n,0) = -1+2^(n+1) = A000225(n+1). %F A094615 T(n,n) = -1+2*3^n = A048473(n). %F A094615 T(2n,n) = -1+2*6^n. %F A094615 T(n,k) = -1 + 2^(n+1-k)*3^k. - _Lamine Ngom_, Feb 10 2021 %e A094615 Triangle begins: %e A094615 n\k| 1 2 3 4 5 6 7 %e A094615 ---+----------------------------------- %e A094615 0 | 1; %e A094615 1 | 3, 5; %e A094615 2 | 7, 11, 17; %e A094615 3 | 15, 23, 35, 53; %e A094615 4 | 31, 47, 71, 107, 161; %e A094615 5 | 63, 95, 143, 215, 323, 485; %e A094615 6 | 127, 191, 287, 431, 647, 971, 1457; %o A094615 (PARI) tabl(nn) = {my(row = [1], nrow); for (n=1, nn, print (row); nrow = vector(n+1, k, if (k<=n, (2*row[k]+1), -1+2*3^n)); row = nrow;);} \\ _Michel Marcus_, Nov 14 2020 %Y A094615 Cf. A094616 (row sums), A094617, A230445. %Y A094615 Cf. A048473, A171498, A198644 %K A094615 nonn,tabl %O A094615 0,2 %A A094615 _Clark Kimberling_, May 14 2004 %E A094615 Offset 0 and more terms from _Michel Marcus_, Nov 14 2020