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 A176550 #7 Feb 18 2019 11:12:49
%S A176550 1,2,3,5,9,11,18,20,21,22,24,29,34,35,42,43,57,61,74,79,81,95,101,102,
%T A176550 111,112,118,120,123,128,136,151,153,154,163,166,167,170,173,177,190,
%U A176550 194,195,198,199,203,205,208,212,213,239,242,245,263,267,271,278,283
%N A176550 Numbers k such that (k-th odd semiprime)/(j-th prime) is prime and ((k+1)-th odd semiprime)/((j+1)-th prime) is prime for some j.
%p A176550 A046315 := proc(n) option remember; if n = 1 then 9; else for a from procname(n-1)+2 by 2 do if numtheory[bigomega](a) = 2 then return a; end if; end do: end if; end proc:
%p A176550 A020639 := proc(n) numtheory[factorset](n) ; min(op(%)) ; end proc:
%p A176550 isA176550 := proc(n) os := A046315(n) ; p := A020639(os) ; q := os/p ; ( A046315(n+1) mod nextprime(p) ) = 0 or (A046315(n+1) mod nextprime(q) = 0 ) ; end proc:
%p A176550 for n from 1 to 300 do if isA176550(n) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, May 30 2010
%Y A176550 Cf. A046315, A084126, A084127, A176484.
%K A176550 nonn
%O A176550 1,2
%A A176550 _Juri-Stepan Gerasimov_, Apr 20 2010
%E A176550 Corrected (39 removed, 43 inserted) and extended by _R. J. Mathar_, May 30 2010