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A206027 a(n) = the number of solutions to sigma(x) = A145899(n). 3
1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 15, 21, 29, 35, 37, 49, 58, 59, 68, 79, 98, 111, 160, 224, 256, 317, 382, 426, 431, 563, 576, 624, 774, 865, 883, 1050, 1195, 1265, 1371, 1376, 1742, 1755, 1935, 2095, 2437, 2447, 2944, 3055, 3318, 3324, 3366, 4289, 4369, 4502 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..100

FORMULA

a(n) = A054973(A145899(n)). - Michel Marcus, Oct 22 2013

EXAMPLE

a(4) = 5 because the 5 numbers x such that sigma(x) = A145899(4) = 72 are x = 30, 46, 51, 55, 71.

MATHEMATICA

t = DivisorSigma[1, Range[10^6]]; t2 = Sort[Tally[t]]; mn = 0; t3 = {}; Do[If[t2[[n]][[2]] > mn, mn = t2[[n]][[2]]; AppendTo[t3, t2[[n]][[2]]]], {n, Length[t2]}]; t3 (* T. D. Noe, Feb 03 2012 *)

CROSSREFS

Cf. A000203 (sigma = sum of divisors of n), A145899, A206026.

Sequence in context: A264387 A282843 A074137 * A039222 A183295 A029927

Adjacent sequences:  A206024 A206025 A206026 * A206028 A206029 A206030

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Feb 03 2012

EXTENSIONS

Extended to 1376 by T. D. Noe, Feb 04 2012

STATUS

approved

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Last modified October 17 10:05 EDT 2019. Contains 328108 sequences. (Running on oeis4.)