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 A151900 #17 Nov 04 2013 11:52:35 %S A151900 19,24,53,59,67,68,73 %N A151900 Singular indices in A139206. %C A151900 Definition: Singular indices in A139206 are numbers n for which there exists no prime p such that p!/n-1 is prime or, if such a prime p exists, it is very big. %C A151900 I frown upon this "definition" and the notion of "very big", especially because A139206(24)=3361 seems to be considered to be "very big"(?!)... A more rigorous definition should be given. - _M. F. Hasler_, Nov 03 2013 %e A151900 From _M. F. Hasler_, Nov 03 2013: (Start) %e A151900 The first unknown term in A139206 is A139206(19), which is (if it exists) larger than 25000. Therefore a(1)=19. %e A151900 The term A139206(24)=3361 is "quite large", therefore a(2)=24. %e A151900 The next unknown term in A139206 is A139206(53), which is also larger than 25000, if it exists. Therefore a(3)=53. (End) %Y A151900 Cf. A139074, A139206, A151901. %K A151900 hard,more,nonn %O A151900 1,1 %A A151900 _Artur Jasinski_, Apr 12 2008 %E A151900 Edited, corrected and extended by _M. F. Hasler_, Nov 03 2013