A155913 Primes p such that (sum of digits of p) - (last digit of p) is prime.

23, 29, 31, 37, 53, 59, 71, 73, 79, 113, 127, 149, 163, 167, 211, 233, 239, 251, 257, 293, 307, 347, 349, 383, 389, 419, 431, 433, 439, 479, 491, 499, 503, 509, 521, 523, 563, 569, 587, 613, 617, 619, 653, 659, 673, 677, 701, 709, 743, 761, 769, 839, 853, 857

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

Presumably a(n) ~ n log n log log n. - Charles R Greathouse IV, Jan 02 2013

Example

113 is in the sequence because it is prime and its sum of digits (1+1+3 = 5) - final digit(3) is prime (5-3 = 2).

Maple

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end: A010879 := proc(n) n mod 10 ; end: for i from 1 to 300 do p := ithprime(i) ; if isprime(A007953(p)-A010879(p)) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Jan 31 2009

Mathematica

Select[Prime[Range[200]], PrimeQ[Total[IntegerDigits[#]] - Last[IntegerDigits[#]]] &] (* Vladimir Joseph Stephan Orlovsky, Feb 15 2012 *)

Prog

(PARI) is(n)=isprime(sumdigits(n) - n%10) && isprime(n) \\ Charles R Greathouse IV, Jan 02 2013

Crossrefs

Cf. A000040.

Sequence in context: A049483 A112681 A078500 * A227919 A240898 A244077

Adjacent sequences: A155910 A155911 A155912 * A155914 A155915 A155916

Keyword

nonn,base

Author

Juri-Stepan Gerasimov, Jan 30 2009

Extensions

Corrected by R. J. Mathar, Jan 31 2009

Status

approved