cp's OEIS Frontend

A065342 Triangle of sum of two primes: prime(n)+prime(k) with n >= k >= 1.

%I A065342 #22 Sep 10 2021 06:08:00
%S A065342 4,5,6,7,8,10,9,10,12,14,13,14,16,18,22,15,16,18,20,24,26,19,20,22,24,
%T A065342 28,30,34,21,22,24,26,30,32,36,38,25,26,28,30,34,36,40,42,46,31,32,34,
%U A065342 36,40,42,46,48,52,58,33,34,36,38,42,44,48,50,54,60,62,39,40,42,44,48
%N A065342 Triangle of sum of two primes: prime(n)+prime(k) with n >= k >= 1.
%H A065342 Reinhard Zumkeller, <a href="/A065342/b065342.txt">First 125 rows of triangle, flattened</a>
%H A065342 <a href="/index/Go#Goldbach">Index entries for sequences related to Goldbach conjecture</a>
%F A065342 T(n, k) = 2*A065305(n, k) [but note different offset].
%e A065342 Sequence starts 2+2; 3+2, 3+3; 5+2, 5+3, 5+5; etc. i.e. 4; 5,6; 7,8,10; ...
%e A065342 Triangle begins:
%e A065342    4;
%e A065342    5,  6;
%e A065342    7,  8, 10;
%e A065342    9, 10, 12, 14;
%e A065342   13, 14, 16, 18, 22;
%e A065342   ...
%o A065342 (Haskell)
%o A065342 import Data.List (inits)
%o A065342 a065342 n k = a065342_tabl !! (n-1) !! (k-1)
%o A065342 a065342_row n = a065342_tabl !! (n-1)
%o A065342 a065342_tabl = zipWith (map . (+)) a000040_list $ tail $ inits a000040_list
%o A065342 -- _Reinhard Zumkeller_, Aug 02 2015, Jan 30 2012
%o A065342 (PARI) row(n) = vector(n, k, prime(n)+prime(k)); \\ _Michel Marcus_, Sep 10 2021
%Y A065342 Cf. A052147 (left edge), A100484 (right edge), A000040.
%Y A065342 Cf. A087112.
%Y A065342 Cf. A065305.
%K A065342 nonn,tabl
%O A065342 1,1
%A A065342 _Henry Bottomley_, Oct 30 2001