A108610 Semiprimes with prime sum of decimal digits and prime sum of prime factors.

34, 58, 142, 214, 274, 298, 382, 454, 478, 562, 694, 838, 922, 1042, 1138, 1198, 1282, 1318, 1642, 1714, 2038, 2098, 2122, 2182, 2302, 2458, 2638, 2854, 2902, 2962, 3334, 3394, 3442, 3574, 3754, 3862, 4054, 4162, 4258, 4474, 4618, 4762, 5314, 5374, 5422

Offset

1,1

Comments

Intersection of A108605 and A108606. All terms are even. Cf. A001358 semiprimes, A101605 3-almost primes, A108605 semiprimes with prime sum of factors, A108606 semiprimes with prime sum of digits.

Links

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

Example

34=2*17 (semiprime), with 3+4=7 and 2+17=19 both prime.

Mathematica

psddQ[n_]:=!IntegerQ[Sqrt[n]]&&PrimeOmega[n]==2&&PrimeQ[Total[ IntegerDigits[n]]] && PrimeQ[Total[Transpose[FactorInteger[n]][[1]]]]; Select[Range[5500], psddQ] (* Harvey P. Dale, Oct 03 2012 *)

Crossrefs

Cf. A001358, A101605, A108605, A108606.

Sequence in context: A103558 A103686 A211715 * A261314 A119454 A259952

Adjacent sequences: A108607 A108608 A108609 * A108611 A108612 A108613

Keyword

nonn,base

Author

Zak Seidov, Jun 12 2005

Status

approved