A245759 Primes p such that concatenation of p with its digit sum is also prime.

61, 83, 137, 139, 197, 199, 223, 241, 281, 313, 337, 353, 373, 397, 421, 449, 557, 577, 647, 719, 773, 809, 881, 937, 953, 971, 991, 1033, 1039, 1091, 1093, 1097, 1129, 1187, 1217, 1277, 1291, 1297, 1303, 1321, 1361, 1381, 1523, 1543, 1567, 1657, 1693, 1723, 1907

Offset

1,1

Links

K. D. Bajpai, Table of n, a(n) for n = 1..8160

Example

61 is in the sequence because it is prime and the concatenation[ 61 with (6 + 1)] = 617 is also prime.
197 is in the sequence because it is prime and the concatenation[ 197 with (1 + 9 + 7)] = 19717 is also prime.

Maple

with(StringTools): A245759 := proc() local a, b, d, e; a:=ithprime(m); b:=add( i, i = convert((a), base, 10))(a); d:=parse(cat(a, b)); e:= parse(cat(b, a)); if isprime(d) then RETURN (a); fi; end: seq(A245759 (), m=1..1000);

Prog

(PARI)
for(n=1, 10^3, p=prime(n); if(isprime(eval(concat(Str(p), Str(sumdigits(p))))), print1(p, ", "))) \\ Derek Orr, Jul 31 2014

Crossrefs

Cf. A000040, A019518, A105184, A244424, A246428.

Sequence in context: A353598 A253232 A345239 * A186457 A103812 A047272

Adjacent sequences: A245756 A245757 A245758 * A245760 A245761 A245762

Keyword

nonn,base

Author

K. D. Bajpai, Jul 31 2014

Status

approved