The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A172508 Prime numbers such that the differences between any pair of digits is prime. 3
 2, 3, 5, 7, 13, 29, 31, 41, 47, 53, 61, 79, 83, 97, 163, 257, 461, 479, 503, 613, 631, 641, 683, 853, 863, 947, 2749, 4297, 4729 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS No further term between 4729 and 7368787 = A000040(500000). - R. J. Mathar, Feb 16 2010 As Robert G. Wilson v points out, there are only 4 different single-digit primes, 2, 3, 5 and 7. Therefore the difference between any pair of a term cannot be zero; the terms can only have a maximum of 5 different digits. A full search covering this range shows that the sequence terminates with the 4729. - R. J. Mathar, Feb 25 2010 LINKS Table of n, a(n) for n=1..29. MAPLE isA172508 := proc(n) local res, dgs, k, l ; dgs := convert(n, base, 10) ; if nops(dgs) < 2 or not isprime(n) then return false; else for k from 1 to nops(dgs)-1 do for l from k+1 to nops(dgs) do if not isprime(abs( op(k, dgs)-op(l, dgs) )) then return false; end if; end do ; end do ; end if; return true; end proc: for i from 1 to 500000 do p := ithprime(i) : if isA172508(p) then printf("%d, \n", p) ; end if; end do: # R. J. Mathar, Feb 16 2010 MATHEMATICA Select[Prime[Range[638]], And@@PrimeQ[#[[1]]-#[[2]]&/@ Subsets[ IntegerDigits[ #], {2}]]&] (* Harvey P. Dale, Nov 29 2012 *) CROSSREFS Sequence in context: A115261 A063792 A270391 * A272107 A227880 A167134 Adjacent sequences: A172505 A172506 A172507 * A172509 A172510 A172511 KEYWORD nonn,base,fini,full AUTHOR Claudio Meller, Feb 05 2010 EXTENSIONS Three more terms from R. J. Mathar and Robert G. Wilson v, Feb 16 2010 Edited by N. J. A. Sloane, Feb 24 2010 Keywords:fini,full added by Ray Chandler and R. J. Mathar, Feb 25 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 2 07:05 EST 2024. Contains 370460 sequences. (Running on oeis4.)