login
A176257
Numbers of the form 4k-1 with greatest prime divisor of the form 4m+1.
6
15, 39, 51, 75, 87, 91, 111, 119, 123, 135, 143, 159, 183, 187, 195, 203, 219, 255, 259, 267, 287, 291, 303, 319, 327, 339, 351, 371, 375, 407, 411, 427, 435, 447, 451, 455, 459, 471, 507, 511, 519, 543, 551, 555, 579, 583, 591, 595, 615, 623, 663, 667, 671
OFFSET
1,1
COMMENTS
By definition, all terms are composite numbers.
LINKS
MATHEMATICA
Select[4*Range[200]-1, Divisible[FactorInteger[#][[-1, 1]]-1, 4]&] (* Harvey P. Dale, May 17 2013 *)
PROG
(PARI) isok(n) = ((n % 4) == 3) && ((vecmax(factor(n)[, 1]) % 4) == 1); \\ Michel Marcus, Feb 07 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Apr 13 2010
EXTENSIONS
Corrected and extended by Harvey P. Dale, May 17 2013
STATUS
approved