A076567 Greatest prime divisor of 4n+6 (sum of four successive integers).

5, 7, 3, 11, 13, 5, 17, 19, 7, 23, 5, 3, 29, 31, 11, 7, 37, 13, 41, 43, 5, 47, 7, 17, 53, 11, 19, 59, 61, 7, 13, 67, 23, 71, 73, 5, 11, 79, 3, 83, 17, 29, 89, 13, 31, 19, 97, 11, 101, 103, 7, 107, 109, 37, 113, 23, 13, 17, 11, 41, 5, 127, 43, 131, 19, 5, 137, 139, 47, 13

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(n) = A076565(n+1) = A006530(4n+6). - R. J. Mathar, Jul 31 2008

Maple

f:= n -> max(numtheory:-factorset(n)):
map(f, [seq(i, i=10..1000, 4)]); # Robert Israel, Nov 10 2020

Mathematica

FactorInteger[#][[-1, 1]]&/@(4*Range[70]+6) (* Harvey P. Dale, Mar 12 2017 *)

Prog

(PARI) a(n) = {f = factor(4*n+6); return (f[length(f~), 1]); } \\ Michel Marcus, Apr 19 2013
(PARI) a(n) = vecmax(factor(4*n+6)[, 1]); \\ Michel Marcus, Nov 10 2020

Crossrefs

Cf. A006530, A076565.

Sequence in context: A144543 A205135 A356360 * A146535 A141650 A058091

Adjacent sequences: A076564 A076565 A076566 * A076568 A076569 A076570

Keyword

easy,nonn

Author

Zak Seidov, Oct 19 2002

Status

approved