A158195 Prime numbers such that sum of digits is even semiprime.

13, 19, 31, 37, 59, 73, 103, 109, 127, 149, 163, 167, 181, 211, 239, 257, 271, 293, 307, 347, 383, 419, 433, 491, 499, 509, 523, 541, 563, 613, 617, 631, 653, 743, 761, 769, 787, 811, 859, 877, 941, 967, 1009, 1021, 1049, 1063, 1117, 1153, 1171, 1193, 1201

Offset

1,1

Comments

Even semiprime = 2*prime.

Links

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

Example

13(1+3=2*2), 19(1+9=2*5), 31(3+1=2*2), 37(3+7=2*5), 59(5+9=2*7).

Mathematica

Select[Prime[Range[200]], PrimeQ[Total[IntegerDigits[#]]/2]&] (* Peter J. C. Moses, Jun 05 2014 *)
Select[Prime[Range[200]], EvenQ[Total[IntegerDigits[#]]]&& PrimeOmega[ Total[ IntegerDigits[ #]]] ==2&] (* Harvey P. Dale, Sep 30 2016 *)

Prog

(PARI) isok(n) = isprime(n) && (q = sumdigits(n)/2) && (type(q) == "t_INT") && isprime(q); \\ Michel Marcus, Jun 24 2014

Crossrefs

Cf. A000040, A100484.

Sequence in context: A272382 A376830 A115093 * A040092 A079130 A243587

Adjacent sequences: A158192 A158193 A158194 * A158196 A158197 A158198

Keyword

nonn,base,easy,less

Author

Juri-Stepan Gerasimov, Mar 13 2009

Extensions

257 added by R. J. Mathar, Mar 15 2009

Status

approved