A174226 Partial sums of A034897.

6, 27, 55, 356, 681, 1177, 1874, 3207, 5116, 7157, 9290, 13191, 21319, 32012, 48525, 68046, 92647, 119624, 170925, 267286, 397439, 557280, 720481, 897142, 1111415, 1361736, 1637569, 1933910, 2240091, 2629684, 3116561, 3612090, 4154503

Offset

1,1

Comments

Partial sums of hyperperfect numbers. The subsequence of prime values in this partial sum begins: 21319, 92647, 720481.

Links

Table of n, a(n) for n=1..33.

Formula

a(n) = SUM[i=1..n] A034897(i) = SUM[i=1..n] {m such that k*sigma(m) = (k+1)*m + k - 1 for some positive integer k, and sigma being the divisor function A000005; noting that k=1 gives perfect numbers}.

Example

a(x) = 6 + 21 + 28 + 301 + 325 + 496 + 697 + 1333 + 1909 + 2041 + 2133 + 3901 + 8128 + 10693 + 16513 + 19521 + 24601 = 92647 is prime.

Crossrefs

Cf. A034897, A034898, A007592, A019279.

Sequence in context: A183603 A067876 A309337 * A100784 A174974 A273578

Adjacent sequences: A174223 A174224 A174225 * A174227 A174228 A174229

Keyword

nonn

Author

Jonathan Vos Post, Mar 12 2010

Status

approved