These are the primes p for the p-adic valuation of A220449 has a well-defined oscillation.
See Moll (2012) for precise definition.
Table of n, a(n) for n=1..30.
V. H. Moll, An arithmetic conjecture on a sequence of arctangent sums, 2012.
Sequence in context: A095103 A094843 A094845 * A155770 A153169 A090797
Adjacent sequences: A220443 A220444 A220445 * A220447 A220448 A220449
N. J. A. Sloane, Dec 22 2012