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

1,1

Links

Table of n, a(n) for n=1..60.

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 *)

Prog

(PARI) lista(nn) = forcomposite(c=1, nn, my(s=sumdigits(c)); if ((s==1) || isprime(s), print1(c, ", "))); \\ Michel Marcus, Nov 15 2019
(Magma) [k:k in [2..230]| not IsPrime(k) and (IsPrime(&+Intseq(k)) or &+Intseq(k) eq 1) ]; // Marius A. Burtea, Feb 05 2020

Crossrefs

Cf. A046704, A104213, A141642, A228019.

Sequence in context: A375213 A092132 A088170 * A189555 A116612 A068502

Adjacent sequences: A329519 A329520 A329521 * A329523 A329524 A329525

Keyword

nonn,base,easy

Author

Ali Adams, Nov 15 2019

Status

approved