A339971 Odd part of A339821(n).

1, 1, 1, 1, 3, 3, 3, 3, 5, 5, 5, 5, 15, 15, 15, 15, 3, 3, 3, 3, 9, 9, 9, 9, 15, 15, 15, 15, 45, 45, 45, 45, 1, 1, 1, 1, 3, 3, 3, 3, 5, 5, 5, 5, 15, 15, 15, 15, 3, 3, 3, 3, 9, 9, 9, 9, 15, 15, 15, 15, 45, 45, 45, 45, 9, 9, 9, 9, 27, 27, 27, 27, 45, 45, 45, 45, 135, 135, 135, 135, 27, 27, 27, 27, 81, 81, 81, 81, 135

Offset

0,5

Links

Table of n, a(n) for n=0..88.

Formula

If 4n = 2^e1 + 2^e2 + ... + 2^ek [e1 ... ek distinct], then a(n) = A057023(e1) * A057023(e2) * ... * A057023(ek).

a(n) = A053575(A019565(2n)) = A336466(A003961(A019565(n))) = A000265(A339821(n)).

a(n) = A339821(n) / A000079(A339822(n)).

Prog

(PARI)
A000265(n) = (n>>valuation(n, 2));
A339971(n) = { my(m=1, p=2); while(n>0, p = nextprime(1+p); if(n%2, m *= A000265(p-1)); n >>= 1); (m); };

Crossrefs

Cf. A000010, A000265, A003961, A019565, A053575, A057023, A336466, A339821, A339822, A339970.

Cf. A339972 (quadrisection).

Sequence in context: A130821 A352226 A129756 * A156724 A196186 A075753

Adjacent sequences: A339968 A339969 A339970 * A339972 A339973 A339974

Keyword

nonn

Author

Antti Karttunen, Dec 26 2020

Status

approved