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%I #26 Mar 13 2023 07:35:02
%S 1,2,3,5,6,7,8,9,10,11,15,21,29,35,37,49,58,59,68,79,98,111,160,224,
%T 256,317,382,426,431,563,576,624,774,865,883,1050,1195,1265,1371,1376,
%U 1742,1755,1935,2095,2437,2447,2944,3055,3318,3324,3366,4289,4369,4502
%N a(n) = the number of solutions to sigma(x) = A145899(n).
%H Donovan Johnson, <a href="/A206027/b206027.txt">Table of n, a(n) for n = 1..100</a>
%F a(n) = A054973(A145899(n)). - _Michel Marcus_, Oct 22 2013
%e a(4) = 5 because the 5 numbers x such that sigma(x) = A145899(4) = 72 are x = 30, 46, 51, 55, 71.
%t 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 *)
%Y Cf. A000203 (sigma = sum of divisors of n), A145899, A206026.
%K nonn
%O 1,2
%A _Jaroslav Krizek_, Feb 03 2012
%E Extended to 1376 by _T. D. Noe_, Feb 04 2012
%E Terms a(41) and beyond from _Donovan Johnson_, Feb 04 2012
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