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.

A342979 a(1) = 2. For n > 1, a(n) is the smallest prime p > a(n-1) such that a(n-1) + p is a 4-almost prime (A014613).

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%I A342979 #15 Apr 10 2021 22:49:00
%S A342979 2,79,131,163,167,173,191,199,263,269,277,281,283,337,349,359,367,373,
%T A342979 397,401,419,431,439,491,521,541,557,593,599,607,613,617,619,659,677,
%U A342979 733,751,757,761,811,857,877,907,911,919,1009,1021,1039,1051,1097,1129,1163,1181,1237,1279
%N A342979 a(1) = 2. For n > 1, a(n) is the smallest prime p > a(n-1) such that a(n-1) + p is a 4-almost prime (A014613).
%C A342979 Minimal difference 2 occurs at positions 12, 32, 86, 118, 155, 242, 345, 427, 430, 517, .... E.g., 2 = 283 - 281 = 619 - 617 = 2083 - 2081.
%e A342979 2 + 79 = 81 = A014613(8), 79 + 131 = 210 = A014613(27).
%t A342979 s = {2}; p = 2; Do[q = NextPrime[p]; While[4 != PrimeOmega[p + q], q = NextPrime[q]]; AppendTo[s, p = q], {55}]; s
%Y A342979 Cf. A000040, A014613.
%K A342979 nonn
%O A342979 1,1
%A A342979 _Zak Seidov_, Apr 02 2021