A074369 Number of divisors of Sum_{i=1..n} prime(i).

2, 2, 4, 2, 6, 2, 4, 4, 9, 4, 12, 2, 8, 2, 8, 4, 16, 4, 8, 6, 8, 4, 8, 6, 12, 8, 10, 4, 16, 8, 16, 4, 12, 4, 6, 4, 16, 4, 8, 12, 8, 6, 8, 4, 12, 4, 8, 4, 16, 8, 12, 12, 16, 4, 4, 8, 16, 4, 4, 2, 8, 6, 8, 2, 4, 4, 8, 8, 8, 8, 16, 4, 8, 8, 4, 8, 16, 6, 20, 12, 6, 4, 12, 16, 16, 8, 24, 12, 12, 8, 24

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000005(A007504(n)). - Amiram Eldar, Mar 09 2020

Example

The number of divisors of prime(1) + prime(2) + prime(3) = 2 + 3 + 5 = 10 is 4, so a(3) = 4.

Mathematica

s = 0; l = {}; Do[s = s + Prime[i]; l = Append[l, DivisorSigma[0, s]], {i, 1, 100}]; l

Crossrefs

Cf. A000005, A007504.

Sequence in context: A284476 A082174 A278235 * A323407 A354875 A073348

Adjacent sequences: A074366 A074367 A074368 * A074370 A074371 A074372

Keyword

easy,nonn

Author

Joseph L. Pe, Sep 24 2002

Status

approved