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 A117710 #7 Sep 25 2024 11:53:14
%S A117710 0,1,5,51,70,210,330,590,715,1001,1080,1162,1520,1820,2035,2380,2501,
%T A117710 3015,3290,3725,4030,4510,5017,5370,6112,6305,6501,6700,6902,7107,
%U A117710 7740,8400,9087,9560,9801,10045,10292,10542,10795,11051,11310,11572,12105
%N A117710 Pentagonal numbers for which the product of the digits is also a pentagonal number.
%e A117710 715 is in the sequence because it is a pentagonal number and the product of its digits 7*1*5=35 is also a pentagonal number.
%t A117710 pn=Table[n (3 n - 1)/2, {n, 0, 90}] ;Select[pn,MemberQ[pn,Times@@IntegerDigits[#]]&] (* _James C. McMahon_, Sep 25 2024 *)
%Y A117710 Cf. A000326, A061380.
%K A117710 base,nonn
%O A117710 0,3
%A A117710 Luc Stevens (lms022(AT)yahoo.com), Apr 13 2006