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A076664 a(n) = Sum_{k=1,...,n} antisigma(k), where antisigma(i) = sum of the nondivisors of i that are between 1 and i. 5
0, 0, 2, 5, 14, 23, 43, 64, 96, 133, 187, 237, 314, 395, 491, 596, 731, 863, 1033, 1201, 1400, 1617, 1869, 2109, 2403, 2712, 3050, 3400, 3805, 4198, 4662, 5127, 5640, 6181, 6763, 7338, 8003, 8684, 9408, 10138, 10957, 11764, 12666, 13572, 14529, 15538 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Sum of all proper nondivisors of all positive integers <= n. - Omar E. Pol, Feb 11 2014

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000292(n) - A024916(n), n >= 1. Omar E. Pol, Feb 11 2014

EXAMPLE

a(5) = antisigma(1) + ... + antisigma(5) = 0 + 0 + 2 + 3 + 9 = 14.

MATHEMATICA

l = {}; s = 0; Do[s = s + (n (n + 1) / 2) - DivisorSigma[1, n]; l = Append[l, s], {n, 1, 100}]; l

Accumulate[Table[Total[Complement[Range[n], Divisors[n]]], {n, 50}]] (* Harvey P. Dale, May 19 2014 *)

CROSSREFS

Cf. A024816.

Sequence in context: A176191 A265248 A131661 * A220477 A049939 A240401

Adjacent sequences:  A076661 A076662 A076663 * A076665 A076666 A076667

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Oct 24 2002

STATUS

approved

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Last modified June 28 05:07 EDT 2017. Contains 288813 sequences.