

A124569


Numbers k such that k, k+2, k+4 and k+6 are squarefree.


2



1, 11, 13, 15, 17, 29, 31, 33, 35, 37, 51, 53, 55, 65, 67, 83, 85, 87, 89, 91, 101, 103, 105, 107, 109, 127, 137, 139, 155, 157, 159, 161, 177, 179, 181, 191, 193, 195, 197, 199, 209, 211, 213, 215, 217, 227, 229, 231, 233, 235, 247, 249, 251, 253, 263, 265, 267
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

Numbers k, k+2, k+4 and k+6 are four successive odd squarefree numbers.


LINKS



MAPLE

filter:= proc(n) andmap(numtheory:issqrfree, [n, n+2, n+4, n+6]) end proc:
select(filter, [seq(i, i=1..1000, 2)]); # Robert Israel, Jun 08 2021


MATHEMATICA

okQ[n_] := AllTrue[n + {0, 2, 4, 6}, SquareFreeQ];


PROG

(PARI) isok(n) = issquarefree(n) && issquarefree(n+2) && issquarefree(n+4) && issquarefree(n+6); \\ Michel Marcus, Oct 11 2013


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



