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A145325
Least k such that f(n,k) is not a prime, where f(n,1)=2n+1 and f(n,k)=f(f(n,k-1)) for k>=2.
2
3, 5, 2, 1, 4, 2, 1, 2, 2, 1, 3, 1, 1, 3, 2, 1, 1, 2, 1, 4, 2, 1, 2, 1, 1, 3, 1, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 3, 1, 1, 5, 1, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 3, 1, 1, 4, 2, 1, 1, 1, 1, 3, 2, 1, 2, 2, 1, 1, 1, 1, 1, 2
OFFSET
1,1
EXAMPLE
f(1,1)=3, f(1,2)=7, f(1,3)=15, so a(1)=3.
For n=1,2,3,4,5, the first few f's follow:
1: 3,7,15,31,63
2: 5,11,23,47,95
3: 7,15,31,63,127
4: 9,19,39,77,159
5: 11,23,47,95,191
CROSSREFS
Sequence in context: A183206 A197521 A161865 * A282194 A138508 A353712
KEYWORD
easy,nonn
AUTHOR
Clark Kimberling, Oct 07 2008
STATUS
approved