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
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