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.

A309152 Numbers that can be written as the sum of two primes whose difference is also prime.

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%I A309152 #16 Jul 15 2019 22:25:01
%S A309152 7,8,9,12,15,21,24,33,36,45,60,63,75,84,105,111,120,141,144,153,183,
%T A309152 195,201,204,216,231,243,273,276,285,300,315,351,360,384,396,423,435,
%U A309152 456,465,480,525,540,564,573,603,621,624,645,663,696,813,825,831,840
%N A309152 Numbers that can be written as the sum of two primes whose difference is also prime.
%C A309152 Numbers k such that k = p + q where p < q and p, q, and q - p are all prime.
%C A309152 Union of A054735 and (A006512 + 2). - _Robert Israel_, Jul 15 2019
%C A309152 From _Bernard Schott_, Jul 15 2019: (Start)
%C A309152 If k is even, then k is in A054735 with q - p = 2.
%C A309152 If k is odd, then k is in (A006512 + 2) with p = 2. (End)
%H A309152 Robert Israel, <a href="/A309152/b309152.txt">Table of n, a(n) for n = 1..10000</a>
%p A309152 P:= select(isprime, {seq(i,i=3..10000,2)}):
%p A309152 T:= P intersect map(`+`,P,2):
%p A309152 A1:= map(`+`,T, 2):
%p A309152 A2:= select(`<`, map(t -> 2*t-2, T), max(A1)):
%p A309152 sort(convert(A1 union A2,list); # _Robert Israel_, Jul 15 2019
%o A309152 (PARI) is(n) = my(x=n-1, y=1); while(x >= y, if(ispseudoprime(x) && ispseudoprime(y), if(ispseudoprime(x-y), return(1))); x--; y++); 0 \\ _Felix Fröhlich_, Jul 14 2019
%Y A309152 Cf. A006512, A054735.
%K A309152 nonn
%O A309152 1,1
%A A309152 _Wesley Ivan Hurt_, Jul 14 2019