A036923 Odd composite numbers n such that the digit sum of n equals digit sum of sum of its prime factors (counted with multiplicity).

27, 105, 121, 265, 315, 355, 445, 517, 841, 913, 915, 1111, 1165, 1185, 1219, 1221, 1239, 1255, 1345, 1363, 1507, 1633, 1903, 2067, 2101, 2155, 2173, 2209, 2227, 2245, 2265, 2335, 2409, 2515, 2533, 2605, 2965, 3091, 3129, 3219, 3235, 3417, 3505, 3507

Offset: 1

Author

Patrick De Geest, Jan 04 1999

Keywords

• nonn
• base

Crossrefs

Cf. A006753, A036920, A019506.

Programs

Mathematica

ds[n_]:=Total[IntegerDigits[n]]; t={}; Do[If[!PrimeQ[n]&&ds[n]==ds[Total[ Times@@@FactorInteger[n]]],AppendTo[t,n]],{n,9,3508,2}]; t (* Jayanta Basu, Jun 04 2013 *)

Extensions

Title reworded by Sean A. Irvine, Nov 30 2020