A366812 The sum of the divisors of prime(n)#+1 where p# is the product of all the primes from 2 to p inclusive.

3, 4, 8, 32, 212, 2312, 30600, 544880, 9727992, 223796952, 6500793728, 200560490132, 7461870828048, 309238687200848, 13161101219883792, 615548170519961184, 33465582319854797280, 1930276657976815787040, 117814338226489513454272, 7858321551223903311137992

Offset: 0

Author

Sean A. Irvine, Oct 23 2023

Keywords

• nonn

Examples

			a(6) = 30600 because the divisors of 13#+1 = 30031 are {1, 59, 509, 30031}.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 0..98

Crossrefs

Cf. A006862, A000230, A054988, A366809, A366811, A366757.

Programs

Maple

seq(numtheory[sigma](mul(ithprime(k), k=1..n)-1), n=0..30);

Mathematica

Map[DivisorSigma[1, #] &, 1 + FoldList[Times, 1, Prime@ Range@ 19] ] (* Michael De Vlieger, Oct 25 2023 *)

Formula

a(n) = sigma(prime(n)#+1) = A000230(A006862(n)).