A341347 a(n) = (1+A003961(A003961(n)))/2 mod 3, where A003961 shifts the prime factorization of n one step towards larger primes.

1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Index entries for sequences computed from indices in prime factorization

Formula

a(n) = A341346(A048673(n)) = A341345(A003961(n)) = A010872(A048673(A003961(n))).

a(n) = [A340683(n) == 0], where [ ] is the Iverson bracket.

Prog

(PARI)
A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
A341347(n) = ((A003961(A003961(n))+1)/2)%3;

Crossrefs

Cf. A003961, A010872, A048673, A292251, A340683, A341345, A341346.

Sequence in context: A156258 A132138 A141212 * A137893 A108882 A369989

Adjacent sequences: A341344 A341345 A341346 * A341348 A341349 A341350

Keyword

nonn

Author

Antti Karttunen, Feb 09 2021

Status

approved