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A152967
Partial sums of A152770.
1
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
OFFSET
1,6
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
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Dec 22 2008
STATUS
approved