A333950 Odd recursive abundant numbers: odd numbers k such that A333926(k) > 2*k.

1575, 2205, 3465, 4095, 5355, 5775, 5985, 6435, 6825, 7245, 8085, 8415, 8925, 9135, 9555, 9765, 11025, 11655, 12705, 12915, 13545, 14805, 15015, 16695, 17325, 18585, 19215, 19635, 20475, 21105, 21945, 22365, 22995, 23205, 24255, 24885, 25935, 26145, 26565, 26775

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

1575 is a term since it is odd and A333926(1575) = 3224 > 2 * 1575.

Mathematica

recDivQ[n_, 1] = True; recDivQ[n_, d_] := recDivQ[n, d] = Divisible[n, d] && AllTrue[FactorInteger[d], recDivQ[IntegerExponent[n, First[#]], Last[#]] &]; recDivs[n_] := Select[Divisors[n], recDivQ[n, #] &]; f[p_, e_] := 1 + Total[p^recDivs[e]]; recDivSum[1] = 1; recDivSum[n_] := Times @@ (f @@@ FactorInteger[n]); Select[2*Range[15000] + 1, recDivSum[#] > 2*# &]

Crossrefs

Intersection of A005408 and A333928.

Cf. A333926.

Analogous sequences: A005231, A094889 (nonunitary), A129485 (unitary), A127666 (infinitary), A293186 (bi-unitary), A321147 (exponential).

Sequence in context: A202465 A045291 A125014 * A357697 A248694 A075460

Adjacent sequences: A333947 A333948 A333949 * A333951 A333952 A333953

Keyword

nonn

Author

Amiram Eldar, Apr 11 2020

Status

approved