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.

A240714 Even numbers whose unordered two primes decomposition set does not contain two groups of n = p1+p2 = p3+p4 such that |p1-p3| = 6 or 12.

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%I A240714 #13 May 01 2014 05:18:16
%S A240714 2,4,6,8,10,12,14,16,18,20,32,68,152,458
%N A240714 Even numbers whose unordered two primes decomposition set does not contain two groups of n = p1+p2 = p3+p4 such that |p1-p3| = 6 or 12.
%C A240714 p1=p2 or p3=p4 allowed.
%C A240714 Conjecture: this sequence is finite and all elements are listed.
%e A240714 For number 152, 152 = 3+149 = 13+139 = 43+109 = 73+79.  The differences of adjacent smaller primes in each of the decomposition groups are 10, 30, 30 respectively.  None of them is 6 or 12.  So 152 is included.
%t A240714 n = 0; Table[
%t A240714 While[n++; s = 2*n; ct = 0; p = 1;
%t A240714   While[p = NextPrime[p]; p <= n,
%t A240714    If[PrimeQ[s - p], ok = 0; a1 = p - 12; b1 = s - a1; a2 = p - 6;
%t A240714     b2 = s - a2; a3 = p + 6; b3 = s - a3; a4 = p + 12; b4 = s - a4;
%t A240714     If[a1 > 0, If[PrimeQ[a1] && PrimeQ[b1], ok = 1]];
%t A240714     If[a2 > 0, If[PrimeQ[a2] && PrimeQ[b2], ok = 1]];
%t A240714     If[a3 <= n, If[PrimeQ[a3] && PrimeQ[b3], ok = 1]];
%t A240714     If[a4 <= n, If[PrimeQ[a4] && PrimeQ[b4], ok = 1]];
%t A240714     If[ok == 1, ct++]]]; ct != 0]; s, {k, 1, 14}]
%Y A240714 Cf. A240713.
%K A240714 nonn,fini
%O A240714 1,1
%A A240714 _Lei Zhou_, Apr 10 2014