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 A333013 #19 Jul 20 2023 17:28:54
%S A333013 2999,6450,6552,7177,8422,9204,9652,10037,10622,11380,11467,16577,
%T A333013 17652,17772,17789,17818,19132,19761,20177,21327,21477,22277,22702,
%U A333013 22855,23008,23212,23387,23427,23444,24402,24662,25677,25847,26286,26902,27649,27802,27847,28567,29927
%N A333013 Integers which can be written in exactly three ways as sum of two distinct nonzero pentagonal numbers.
%e A333013 2999 = P(24) + P(38) = P(13) + P(43) = P(9) + P(44), where P(n) is the n-th pentagonal number A000326.
%t A333013 dnpQ[n_]:=Count[IntegerPartitions[n,{2}],_?(AllTrue[(1+Sqrt[1+24#])/6,IntegerQ]&)]==3; Parallelize[Select[Range[30000],dnpQ]] (* or *) Select[Tally[Total/@Subsets[ PolygonalNumber[ 5,Range[200]],{2}]],#[[2]]==3&][[;;,1]]//Union (* _Harvey P. Dale_, Jul 20 2023 *)
%o A333013 (PARI) is(k) = sum(i=1, sqrt(1+12*k)\6, sqrt(1+24*k+12*i-36*i*i)%6==5) == 3; \\ _Jinyuan Wang_, Mar 06 2020
%Y A333013 Cf. A000326, A333011, A333012, A333014, A333015.
%K A333013 nonn
%O A333013 1,1
%A A333013 _Olivier Gérard_, Mar 05 2020