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A023571 Least odd prime divisor of p(n)-3, or 1 if p(n)-3 is a power of 2. 0
1, 1, 1, 1, 1, 5, 7, 1, 5, 13, 7, 17, 19, 5, 11, 5, 7, 29, 1, 17, 5, 19, 5, 43, 47, 7, 5, 13, 53, 5, 31, 1, 67, 17, 73, 37, 7, 5, 41, 5, 11, 89, 47, 5, 97, 7, 13, 5, 7, 113, 5, 59, 7, 31, 127, 5, 7, 67, 137, 139, 5, 5, 19, 7, 5, 157, 41, 167, 43, 173, 5, 89, 7, 5, 47, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..76.

MATHEMATICA

Join[{1, 1}, Table[If[IntegerQ[Log[2, n-3]], 1, Select[ Transpose[ FactorInteger[ n-3]][[1]], #>2&][[1]]], {n, Prime[Range[3, 80]]}]] (* Harvey P. Dale, Jul 16 2016 *)

CROSSREFS

Sequence in context: A021179 A153613 A318375 * A160631 A155066 A343480

Adjacent sequences:  A023568 A023569 A023570 * A023572 A023573 A023574

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified June 30 19:43 EDT 2022. Contains 354945 sequences. (Running on oeis4.)