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 A284742 #7 Apr 02 2017 12:35:48
%S A284742 1,5,7,9,13,15,25,33,35,55,63,69,91,121,129,147,155,189,195,231,295,
%T A284742 309,341,377,425,427,559,561,575,589,791,833,855,909,923,1035,1159,
%U A284742 1241,1325,1415,1561,1661,1665,1729,2047,2057,2059,2331,2511,2625,2743,2869,3025,3059,3303,3605,3871,3925,4089,4215,4255
%N A284742 Centered Platonic numbers.
%C A284742 Union of centered tetrahedral numbers (A005894), centered octahedral numbers (A001845), centered cube numbers (A005898), centered icosahedral numbers (A005902) and centered dodecahedral numbers (A005904).
%H A284742 OEIS Wiki, <a href="/wiki/Centered_Platonic_numbers">Centered Platonic numbers</a> [Unapproved page]
%t A284742 nn = 18; t1 = Table[(2 n + 1) (n^2 + n + 3)/3, {n, 0, nn}]; t2 = Table[(2 n + 1) (2 n^2 + 2 n + 3)/3, {n, 0, nn}]; t3 = Table[n^3 + (n + 1)^3, {n, 0, nn}]; t4 = Table[(2 n + 1) (5 n^2 + 5 n + 3)/3, {n, 0, nn}]; t5 = Table[(2 n + 1) (5 n^2 + 5 n + 1), {n, 0, nn}]; Select[Union[t1, t2, t3, t4, t5], # <= t1[[-1]] &]
%Y A284742 Cf. A001845, A005894, A005898, A005902, A005904, A053012.
%K A284742 nonn,easy
%O A284742 1,2
%A A284742 _Ilya Gutkovskiy_, Apr 01 2017