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A160664 a(n) = a(n-1) + A000203(n), a(0)=1. 4
1, 2, 5, 9, 16, 22, 34, 42, 57, 70, 88, 100, 128, 142, 166, 190, 221, 239, 278, 298, 340, 372, 408, 432, 492, 523, 565, 605, 661, 691, 763, 795, 858, 906, 960, 1008, 1099, 1137, 1197, 1253, 1343, 1385, 1481 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = 1 + A024916(n). - R. J. Mathar, May 25 2009

a(n) = 9 + A092406(n) for n>3. - Greg Dresden, Feb 23 2020

MAPLE

ListTools:-PartialSums(map(numtheory:-sigma, [1, $1..100])); # Robert Israel, Dec 19 2016

MATHEMATICA

lst = {1}; a = 1; Do[a = a + DivisorSigma[1, n]; AppendTo[lst, a], {n, 80}]; lst (* Carl Najafi, Aug 21 2011 *)

Transpose[NestList[{First[#]+1, Last[#]+DivisorSigma[1, First[#]+1]}&, {0, 1}, 50]][[2]] (* Harvey P. Dale, May 05 2012 *)

PROG

(PARI) a(n)=1+sum(k=1, n, sigma(k)) \\ Charles R Greathouse IV, Aug 22 2011

CROSSREFS

Cf. A054519, A092406, A024916. - Greg Dresden, Feb 23 2020

Sequence in context: A045649 A267694 A024519 * A345140 A072829 A169740

Adjacent sequences:  A160661 A160662 A160663 * A160665 A160666 A160667

KEYWORD

nonn

AUTHOR

Ctibor O. Zizka, May 22 2009

EXTENSIONS

More terms from Carl Najafi, Aug 21 2011

STATUS

approved

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Last modified August 14 05:20 EDT 2022. Contains 356110 sequences. (Running on oeis4.)