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 A259746 #7 Jul 19 2015 12:03:21 %S A259746 15,120,153,351,406,741,1891,3081,3403,4465,5151,5565,6555,9453,9591, %T A259746 18721,22791,38226,39903,46056,52326,79401,85491,91378,159895,187578, %U A259746 207690,222111,227475,229503,266815,274911,280875,326028,334971,354903,373680,410871,474825,609960 %N A259746 Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>1. %C A259746 A subsequence of A000217, A254671 and A259745. %C A259746 Up to 10^12, only 3 terms admit two representations, namely 22791, 410871 and 1675365. - _Giovanni Resta_, Jul 19 2015 %H A259746 Giovanni Resta, <a href="/A259746/b259746.txt">Table of n, a(n) for n = 1..500</a> %e A259746 153 = 6*21 + 6 + 21. %e A259746 351 = 15*21 + 15 + 21. %e A259746 406 = 10*36 + 10 + 36. %Y A259746 Cf. A000217, A254671, A259745. %K A259746 nonn %O A259746 1,1 %A A259746 _Alex Ratushnyak_, Jul 04 2015