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 A086273 #12 Aug 07 2015 03:00:10 %S A086273 1,1,3,1,4,7,1,5,10,13,1,6,13,19,21,1,7,16,25,31,31,1,8,19,31,41,46, %T A086273 43,1,9,22,37,51,61,64,57,1,10,25,43,61,76,85,85,73,1,11,28,49,71,91, %U A086273 106,113,109,91,1,12,31,55,81,106,127,141,145,136,111,1,13,34,61,91,121,148 %N A086273 Rectangular array T(n,k) of central polygonal numbers, by antidiagonals. %C A086273 Transpose of the array at A086272. %H A086273 Clark Kimberling and John E. Brown, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL7/Kimberling/kimber67.html">Partial Complements and Transposable Dispersions</a>, J. Integer Seqs., Vol. 7 (2004) # 04.1.6. %F A086273 T(n, k)=(k+1)*binomial(n, 2)+1. %e A086273 Northwest corner: %e A086273 1 1 1 1 1 1 1 1 1 1 %e A086273 3 4 5 6 7 8 9 10 11 12 A000027 %e A086273 7 10 13 16 19 22 25 28 31 34 A112414, A016777 %e A086273 13 19 25 31 37 43 49 55 61 67 A016921 %e A086273 21 31 41 51 61 71 81 91 101 111 A017281 %e A086273 31 46 61 76 91 106 121 136 151 166 %e A086273 43 64 85 106 127 148 169 190 211 232 %e A086273 57 85 113 141 169 197 225 253 281 309 %e A086273 73 109 145 181 217 253 289 325 361 397 %e A086273 91 136 181 226 271 316 361 406 451 496 %e A086273 111 166 221 276 331 386 441 496 551 606 %e A086273 133 199 265 331 397 463 529 595 661 727 %e A086273 157 235 313 391 469 547 625 703 781 859 %e A086273 183 274 365 456 547 638 729 820 911 1002 %e A086273 211 316 421 526 631 736 841 946 1051 1156 %e A086273 241 361 481 601 721 841 961 1081 1201 1321 %p A086273 A086273 := proc(n,k) (k+1)*n*(n-1)/2+1 ; end proc: # _R. J. Mathar_, Jun 05 2011 %Y A086273 Cf. A086270, A086271, A086272, A086274. %K A086273 nonn,tabl %O A086273 1,3 %A A086273 _Clark Kimberling_, Jul 14 2003