A154784 Row sums of triangle in A154721.

0, 4, 6, 16, 10, 24, 28, 32, 54, 60, 44, 96, 52, 56, 120, 96, 102, 144, 76, 120, 210, 176, 138, 288, 200, 156, 324, 168, 174, 420, 186, 320, 396, 204, 350, 504, 370, 380, 546, 400, 328, 756, 344, 352, 900, 368, 376, 672, 392, 600

Offset: 1

Author

Omar E. Pol, Jan 15 2009

Keywords

• easy
• nonn

Comments

a(n) is even for all n.

Links

• Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A154720, A154721, A154723, A154783, A154785, A154786.

Programs

Maple

isnotcomp:=proc(n)return (n=1 or isprime(n)) end:
for n from 1 to 50 do rsum:=0: for k from 1 to 2*n-1 do if(not k=n and (isnotcomp(k) and isnotcomp(2*n-k)))then rsum:=rsum+k:fi:od: printf("%d, ",rsum):od: # Nathaniel Johnston, Apr 19 2011

Formula

a(n) = A154783(n) - n.

Extensions

Edited by Omar E. Pol, Jan 17 2009

a(11)-a(50) from Nathaniel Johnston, Apr 19 2011