A272638 a(1)=1, a(2)=4; thereafter a(n) = squarefree part of a(n-1)+a(n-2).

1, 4, 5, 1, 6, 7, 13, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7, 1, 2, 3, 5, 2, 7

Offset

1,2

Links

Table of n, a(n) for n=1..88.

Maple

sqrf:= n-> mul(i[1]^irem(i[2], 2), i=ifactors(n)[2]):
f:=proc(n) global sqrf; option remember;
if n = 1 then 1 elif n=2 then 4 else sqrf(f(n-1)+f(n-2)); fi; end;
[seq(f(n), n=1..140)];

Crossrefs

Rapidly merges with A272636.

Cf. A000045, A007913.

Sequence in context: A336885 A094642 A069284 * A365464 A299630 A068447

Adjacent sequences: A272635 A272636 A272637 * A272639 A272640 A272641

Keyword

nonn

Author

N. J. A. Sloane, May 05 2016

Status

approved