A046347 Odd composite numbers divisible by the sum of their prime factors (counted with multiplicity).

27, 105, 231, 627, 805, 897, 945, 1581, 1755, 2079, 2625, 2967, 3055, 3125, 3861, 4185, 4543, 5355, 5445, 5487, 5967, 6075, 6461, 6525, 6745, 7881, 8085, 8505, 8883, 9555, 9717, 10125, 10647, 10707, 11375, 11385, 12675, 12789, 13005, 13275, 13475

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n=1..1000

Example

897 is a term since 897 = 3 * 13 * 23 and 3 + 13 + 23 = 39 and 897 / 39 = 23.

Mathematica

Select[Range[9, 13500, 2], !PrimeQ[#]&&IntegerQ[#/Total[Times@@@FactorInteger[#]]]&] (* Jayanta Basu, Jun 04 2013 *)

Prog

(PARI) sopfr(n) = {my(f=factor(n)); sum(k=1, #f~, f[k, 1]*f[k, 2]); } \\ A001414
lista(nn) = forcomposite(n=2, nn, if ((n%2) && !(n % sopfr(n)), print1(n, ", ")); ); \\ Michel Marcus, Feb 06 2019

Crossrefs

Cf. A001414, A046346, A046348.

Sequence in context: A036923 A036346 A140376 * A158549 A254319 A044278

Adjacent sequences: A046344 A046345 A046346 * A046348 A046349 A046350

Keyword

nonn

Author

Patrick De Geest, Jun 15 1998

Extensions

Name clarified by Michel Marcus, Feb 06 2019

Status

approved