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A126761
{a(k)} is such that, for every positive integer n, the n-th prime = Sum_{k=1..n, gcd(k,n+1)=1} a(k).
1
2, 1, 3, 1, 9, -3, 3, 3, 15, -5, 17, -9, -5, 21, 3, -3, 33, -25, -1, 19, 11, -11, 25, 11, -23, 15, 25, -25, 35, -29, -25, 51, 43, -59, 79, -51, -93, 109, 79, -73, 205, -197, -189, 83, -29, 153, 139, -223, -95, -193, 41, 371, 125, -223, -177, -151, 49, 409, 101
OFFSET
1,1
LINKS
EXAMPLE
31 is the 11th prime. So 31 = Sum_{1<=k<=11, gcd(k,12)=1} a(k) = a(1) + a(5) + a(7) + a(11) = 2 + 9 + 3 + 17.
PROG
(PARI) See Links section.
CROSSREFS
Cf. A000040.
Sequence in context: A136179 A185176 A198315 * A090559 A088640 A186725
KEYWORD
sign
AUTHOR
Leroy Quet, Feb 22 2007
EXTENSIONS
More terms from Rémy Sigrist, Feb 06 2019
STATUS
approved