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A073954 Sum of the anti-divisors of n exceeds 2n. 1
143, 175, 203, 247, 248, 270, 280, 297, 315, 325, 333, 347, 357, 368, 410, 423, 462, 472, 473, 500, 518, 522, 553, 563, 567, 578, 585, 598, 630, 637, 675, 682, 693, 697, 725, 742, 760, 770, 787, 788, 808, 833, 850, 858, 878, 893, 913, 945, 963, 977, 990 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A066272 for definition of anti-divisor.

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..576 (a(n) <= 10,000)

EXAMPLE

a(1) = 143 because A066417(143) = 292, which exceeds 2 * 143 = 286. (A066417 is the sum of anti-divisors of n).

MATHEMATICA

a066417[n_Integer] := Total[Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)]]; Select[Range[10000], If[a066417[#] > 2 #, True, False] &] (* Michael De Vlieger, Aug 09 2014 *)

PROG

(Python)

A073954 = [n for n in xrange(1, 10**5) if sum([d for d in xrange(2, n, 2) if n%d and not 2*n%d])+sum([d for d in xrange(3, n, 2) if n%d and 2*n%d in [d-1, 1]]) > 2*n] # Chai Wah Wu, Aug 09 2014

CROSSREFS

Cf. A066272 (number of anti-divisors of n), A066417 (sum of anti-divisors of n).

Sequence in context: A160781 A217141 A097435 * A227868 A176876 A257767

Adjacent sequences:  A073951 A073952 A073953 * A073955 A073956 A073957

KEYWORD

easy,nonn

AUTHOR

Jason Earls, Sep 03 2002

STATUS

approved

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)