OFFSET

0,2

COMMENTS

Partial sums of number of Giuga sequences of length n. The only known primes in this partial sum are 3 and 23.

FORMULA

a(n) = SUM[i=0..n] A029876(i) = SUM[i=0..n] {numbers i such that p divides i/p - 1 for every prime divisor p of i}.

EXAMPLE

a(4) = 1 + 2 + 3 + 17 + 27 = 50.

CROSSREFS

KEYWORD

nonn

AUTHOR

Jonathan Vos Post, Apr 17 2010

STATUS

approved