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A305892
a(n) = 1 if n is composite and the n-th Stern polynomial B(n,x) is irreducible, 0 otherwise.
2
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1
OFFSET
1
COMMENTS
Characteristic function for A186892, apart from its initial term.
See also A186891 about related Ulas & Ulas conjecture.
FORMULA
a(n) = (1-A010051(n))*A283991(n).
PROG
(PARI)
ps(n)=if(n<2, n, if(n%2, ps(n\2)+ps(n\2+1), 'x*ps(n\2)));
A305892(n) = (!isprime(n) && polisirreducible(ps(n))); \\ Antti Karttunen, Jun 16 2018, after Charles R Greathouse IV's Apr 07 2015 code for A186892.
CROSSREFS
Differs from A305821 for the first time at n=65, where a(65) = 1, while A305821(65) = 0.
Sequence in context: A011739 A023975 A305821 * A324870 A011738 A011737
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 16 2018
STATUS
approved