A206027 a(n) = the number of solutions to sigma(x) = A145899(n).

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

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 A340745 A183295

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

Terms a(41) and beyond from Donovan Johnson, Feb 04 2012

Status

approved