A109959 Numbers n such that concatenating n and the sum of primes dividing n (counting multiplicity) produces a prime.

10, 12, 14, 22, 38, 82, 90, 92, 96, 116, 117, 122, 134, 147, 158, 165, 178, 198, 210, 218, 236, 262, 274, 304, 314, 332, 333, 352, 358, 360, 369, 387, 390, 399, 420, 448, 454, 478, 482, 496, 522, 561, 562, 603, 605, 622, 637, 639, 640, 651, 694, 704, 714, 720

Offset

1,1

Comments

7^50+144 generates a 62 digit prime.

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(5)=38 because 38=2*19 and 19+2=21 and 3821 is prime.

Mathematica

Select[Range[2, 1000], PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ Total[Times@@@FactorInteger[#]]]]]]&] (* Harvey P. Dale, Aug 10 2012 *)

Crossrefs

Cf. A001414, A109958.

Sequence in context: A189555 A116612 A068502 * A161990 A218335 A030591

Adjacent sequences: A109956 A109957 A109958 * A109960 A109961 A109962

Keyword

easy,nonn,base

Author

Jason Earls, Jul 06 2005

Status

approved