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A004625 Numbers divisible only by primes congruent to 1 mod 8. 3
1, 17, 41, 73, 89, 97, 113, 137, 193, 233, 241, 257, 281, 289, 313, 337, 353, 401, 409, 433, 449, 457, 521, 569, 577, 593, 601, 617, 641, 673, 697, 761, 769, 809, 857, 881, 929, 937, 953, 977, 1009, 1033, 1049 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

ok[n_] := And @@ (#1[[2]] == 1 && Mod[#1[[1]], 8] == 1 & ) /@ FactorInteger[n]; Select[ Range[2000], ok] (* Jean-Fran├žois Alcover, Mar 09 2012 *)

PROG

(MAGMA) [n: n in [1..2000] | forall{d: d in PrimeDivisors(n) | d mod 8 eq 1}]; // Vincenzo Librandi, Aug 20 2012

(PARI) is(n)=is(n%8!=1, return(0)); my(f=factor(n)[, 1]); for(i=1, #f~, if(f[i]%8!=1, return(0))); 1 \\ Charles R Greathouse IV, Jul 02 2016

CROSSREFS

Sequence in context: A263011 A263012 A172280 * A141174 A007519 A163185

Adjacent sequences:  A004622 A004623 A004624 * A004626 A004627 A004628

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

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

STATUS

approved

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Last modified January 22 22:38 EST 2018. Contains 298093 sequences.