A329522 Composite numbers whose sum of digits is not composite.

10, 12, 14, 16, 20, 21, 25, 30, 32, 34, 38, 49, 50, 52, 56, 58, 65, 70, 74, 76, 85, 92, 94, 98, 100, 102, 104, 106, 110, 111, 115, 119, 120, 122, 124, 128, 133, 140, 142, 146, 148, 155, 160, 164, 166, 175, 182, 184, 188, 200, 201, 203, 205, 209, 210, 212, 214, 218, 221, 230

Offset: 1

Author

Ali Adams, Nov 15 2019

Keywords

• nonn
• base
• easy

Crossrefs

Cf. A046704, A104213, A141642, A228019.

Programs

Magma

[k:k in [2..230]| not IsPrime(k) and (IsPrime(&+Intseq(k)) or &+Intseq(k) eq 1) ]; // Marius A. Burtea, Feb 05 2020

Mathematica

Select[Rest@ Complement[#, Prime@ Range@ PrimePi@ Max@ #] &@ Range@ 230, ! CompositeQ@ Total@ IntegerDigits@ # &] (* Michael De Vlieger, Nov 15 2019 *)
Select[Range[250],CompositeQ[#]&&!CompositeQ[Total[IntegerDigits[#]]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 19 2021 *)

PARI

lista(nn) = forcomposite(c=1, nn, my(s=sumdigits(c)); if ((s==1) || isprime(s), print1(c, ", "))); \\ Michel Marcus, Nov 15 2019