A221699 Numbers with property that each sum any pair of digits is prime.

11, 12, 14, 16, 20, 21, 23, 25, 29, 30, 32, 34, 38, 41, 43, 47, 49, 50, 52, 56, 58, 61, 65, 67, 70, 74, 76, 83, 85, 89, 92, 94, 98, 111, 112, 114, 116, 121, 141, 161, 203, 205, 211, 230, 250, 302, 320, 411, 502, 520, 611, 1111, 1112, 1114, 1116, 1121, 1141, 1161

Offset: 1

Author

Jaroslav Krizek, Jan 22 2013

Keywords

• nonn
• base

Comments

Supersequence of A091939. Subsequence of A182175.

Examples

			Number 203 is a term because 2+3=5, 2+0=2, 3+0=3 (primes).
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..145

Crossrefs

Cf. A172508, A091939, A182175.

Programs

Mathematica

fQ[n_] := Module[{d = IntegerDigits[n]}, Union[PrimeQ[Plus @@@ Union[Subsets[d, {2}]]]] == {True}]; Select[Range[6000], fQ] (* T. D. Noe, Jan 24 2013 *)
Select[Range[10,1200],AllTrue[Total/@Subsets[IntegerDigits[#],{2}],PrimeQ]&] (* Harvey P. Dale, Jan 31 2024 *)