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 A225789 #10 Jul 25 2019 10:22:14 %S A225789 0,3,6,66,190,45,105,0,2556,1035,5995,8646,1326,16471,210,28680,36856, %T A225789 46971,0,72010,630,3003,32131,16836,20100,52975,246051,17766,329266, %U A225789 42195,17205,491536,0,17391,0,49770,55278,0,30381,5460,0,164451,33411,0,4950,85905,584821 %N A225789 Least triangular number of the form p*triangular(n) where p is a prime number, or 0 if no such triangular number exists. %F A225789 a(n) = A225787(n) * A000217(n). %Y A225789 Cf. A000217, A068084, A225503, A225787. %K A225789 nonn %O A225789 0,2 %A A225789 _Alex Ratushnyak_, May 16 2013 %E A225789 a(28) corrected by _Mansour Qahwaji_, Jul 25 2019