A145327 Least k such that f(n,k) is not a prime, where f(n,1)=4n+1 and f(n,k)=f(f(n,k-1)) for k>=2.

2, 1, 3, 2, 1, 1, 2, 1, 3, 2, 1, 1, 2, 1, 2, 1, 1, 3, 1, 1, 1, 2, 1, 3, 2, 1, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 3, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 3, 2, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Example

f(1,1)=5, f(1,2)=21, so a(1)=2.
f(2,1)=9, so a(2)=1.
f(3,1)=13, f(3,2)=53, f(3,3)=213, so a(3)=3.

Crossrefs

Cf. A145325, A145326.

Sequence in context: A347030 A166949 A114890 * A255191 A277818 A324607

Adjacent sequences: A145324 A145325 A145326 * A145328 A145329 A145330

Keyword

easy,nonn

Author

Clark Kimberling, Oct 07 2008

Status

approved