A152967 - OEIS

A152967

Partial sums of A152770.

0, 0, 0, 1, 1, 4, 4, 8, 10, 15, 15, 26, 26, 33, 39, 50, 50, 66, 66, 83, 91, 102, 102, 131, 135, 148, 158, 181, 181, 216, 216, 242, 254, 271, 281, 328, 328, 347, 361, 404, 404, 451, 451, 486, 514, 537, 537, 604, 610, 648, 666, 707, 707, 766, 780, 837, 857, 886, 886, 983, 983

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OFFSET

1,6

LINKS

B. D. Swan, Table of n, a(n) for n=1..10000

FORMULA

a(n) = Sum_{i=1..n} (i-1)*floor((n-i)/i). - Wesley Ivan Hurt, Sep 13 2017

MATHEMATICA

Accumulate[Array[DivisorSigma[1, #]-DivisorSigma[0, #]-#+1&, 70]] (* Harvey P. Dale, Dec 27 2011 *)

CROSSREFS

Cf. A152770.

Sequence in context: A180854 A014687 A172022 * A376433 A301705 A309456

Adjacent sequences: A152964 A152965 A152966 * A152968 A152969 A152970

KEYWORD

easy,nonn

AUTHOR

Omar E. Pol, Dec 22 2008

STATUS

approved