



1, 2, 6, 11, 17, 25, 34, 45, 58, 73, 89, 108, 128, 150, 174, 201, 229, 260, 292, 327, 364, 403, 443, 487, 533, 581, 631, 684, 738, 796, 855, 917, 981, 1047, 1115, 1188, 1262, 1338, 1416, 1498, 1581, 1668, 1756, 1847, 1941, 2037, 2134, 2236, 2340, 2447, 2556
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OFFSET

1,2


COMMENTS

Partial sums of partial sums of A038548. Partial sums of partial sums of number of divisors of n that are at most sqrt(n). The subsequence of primes in this sequence begins: 2, 11, 17, 73, 89, 229, 443, 487, 631, 1847, 2447. The subsequence of squares in this sequence begins: 1, 25, 4356.


LINKS

Table of n, a(n) for n=1..51.


EXAMPLE

a(11) = 1 + 2 + 3 + 5 + 6 + 8 + 9 + 11 + 13 + 15 + 16 = 89 is prime.


CROSSREFS

Cf. A038548, A094820.
Sequence in context: A046691 A098167 A081689 * A231559 A104813 A239698
Adjacent sequences: A176705 A176706 A176707 * A176709 A176710 A176711


KEYWORD

easy,nonn


AUTHOR

Jonathan Vos Post, Apr 24 2010


STATUS

approved



