A340683 a(n) = A007949((A003961(A003961(n))+1)/2), where A003961 shifts the prime factorization of n one step towards larger primes, and A007949(x) gives the exponent of largest power of 3 dividing x.

0, 1, 0, 0, 1, 2, 0, 2, 0, 0, 2, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 2, 0, 0, 0, 0, 0, 1, 1, 3, 1, 3, 1, 1, 0, 0, 1, 4, 0, 0, 1, 0, 1, 1, 1, 0, 2, 2, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 1, 3, 0, 1, 1, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 1, 0, 2, 1, 0, 3, 0, 0, 3, 1

Offset

1,6

Links

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

Index entries for sequences computed from indices in prime factorization

Formula

a(n) = A292251(A003961(n)) = A007949(A048673(A003961(n))).

Prog

(PARI)
A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
A340683(n) = valuation((A003961(A003961(n))+1)/2, 3);

Crossrefs

Cf. A003961, A007949, A048673, A292251, A341347.

Sequence in context: A035220 A227618 A366533 * A221645 A216176 A359007

Adjacent sequences: A340680 A340681 A340682 * A340684 A340685 A340686

Keyword

nonn

Author

Antti Karttunen, Feb 14 2021

Status

approved