cp's OEIS Frontend

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.

A117101 Numbers k such that nextprime(5*k) > 5*nextprime(k) and k is composite.

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%I A117101 #17 Jul 28 2025 03:15:38
%S A117101 18,28,40,60,72,78,82,96,102,105,106,155,156,166,178,180,192,222,226,
%T A117101 228,250,262,266,267,268,270,280,282,292,312,328,329,330,334,335,336,
%U A117101 352,358,378,387,388,396,408,418,420,436,437,438,460,485,486,490,496,497
%N A117101 Numbers k such that nextprime(5*k) > 5*nextprime(k) and k is composite.
%H A117101 Paolo Xausa, <a href="/A117101/b117101.txt">Table of n, a(n) for n = 1..10000</a>
%t A117101 Select[Range[500], CompositeQ[#] && NextPrime[5*#] > 5*NextPrime[#] &] (* _Paolo Xausa_, Jul 28 2025 *)
%o A117101 (PARI) for(i=1,300,if(nextprime(5*i)>nextprime(5)*nextprime(i) && !isprime(i),print1(i,",")))
%Y A117101 Set difference of A117094 and A000040.
%Y A117101 Intersection of A002808 and A117094.
%Y A117101 Cf. A007918 (nextprime).
%K A117101 easy,nonn
%O A117101 1,1
%A A117101 Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Apr 18 2006
%E A117101 Name simplified by _Paolo Xausa_, Jul 28 2025