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 A133459 #11 Apr 16 2016 20:47:17
%S A133459 2,7,12,19,24,36,41,46,58,76,80,81,93,115,127,132,144,150,166,197,201,
%T A133459 202,214,236,252,271,289,294,306,322,328,363,392,406,411,414,423,445,
%U A133459 480,484,531,551,556,568,576,590,601,625,676,693,727,732,744,746,766
%N A133459 Sums of two nonzero pentagonal pyramidal numbers.
%C A133459 Does this sequence ever include a pentagonal pyramidal number? That is, is it ever the case that A002411(i)=A002411(j)+A002411(k) as is often true for triangular pyramidal numbers (tetrahedral numbers) or square pyramidal numbers?
%C A133459 The answer to the above question is yes: A002411(30) + A002411(36) = 13950 + 23976 = 37926 = A002411(42) (see A172425). - _Chai Wah Wu_, Apr 16 2016
%F A133459 {A002411(i) + A002411(j) for i, j > 0} = {i^2*(i+1)/2 + j^2*(j+1)/2 for i, j > 0}.
%t A133459 nn = 12; Take[Union@ Map[Total, Tuples[#^2 (# + 1)/2 &@ Range@ nn, 2]], # (# - 1)/2 &[nn - 1]] (* _Michael De Vlieger_, Apr 16 2016 *)
%Y A133459 Cf. A002311, A002411, A053721, A172425.
%K A133459 nonn
%O A133459 1,1
%A A133459 _Jonathan Vos Post_, Dec 23 2007