A004624 Divisible only by primes congruent to 6 mod 7.

1, 13, 41, 83, 97, 139, 167, 169, 181, 223, 251, 293, 307, 349, 419, 433, 461, 503, 533, 587, 601, 643, 727, 769, 797, 811, 839, 853, 881, 937, 1021, 1049, 1063, 1079, 1091, 1217, 1231, 1259, 1261, 1301, 1399, 1427, 1483, 1511, 1553, 1567, 1609, 1637, 1681

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

ok[1]=True; ok[n_]:=And@@(Mod[#, 7]==6&)/@FactorInteger[n][[All, 1]]; Select[Range[5000], ok] (* Vincenzo Librandi, Aug 20 2012 *)

Prog

(Magma) [n: n in [1..2000] | forall{d: d in PrimeDivisors(n) | d mod 7 eq 6}]; // Vincenzo Librandi, Aug 20 2012

Crossrefs

Sequence in context: A031373 A043162 A043942 * A045473 A102083 A139866

Adjacent sequences: A004621 A004622 A004623 * A004625 A004626 A004627

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Offset changed from 0 to 1 by Vincenzo Librandi, Aug 20 2012

Status

approved