OFFSET
1,4
FORMULA
a(n) = A154785(n) - n.
MAPLE
A154786 := proc(n) local a, d; a := 0 ; for d from 1 to n-2 do if isprime(n-d) and isprime(n+d) then a := a+2*n; fi; od: a ; end: for n from 1 to 80 do printf("%d, ", A154786(n)) ; od: # R. J. Mathar, Jan 18 2009
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Jan 15 2009, Jan 16 2009
EXTENSIONS
Edited by Omar E. Pol, Jan 17 2009
Extended by R. J. Mathar, Jan 18 2009
STATUS
approved