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

1,2

Comments

a(n) is even for all n.

Links

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

Formula

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

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

Crossrefs

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

Sequence in context: A123667 A129597 A088843 * A328709 A062955 A174932

Adjacent sequences: A154781 A154782 A154783 * A154785 A154786 A154787

Keyword

easy,nonn

Author

Omar E. Pol, Jan 15 2009

Extensions

Edited by Omar E. Pol, Jan 17 2009

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

Status

approved