A212178 Number of exponents >= 2 in canonical prime factorization of A025487(n) (first integer of each prime signature).

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

Offset

1,11

Comments

Length of row n of A212175 equals a(n) if a(n) is positive, 1 otherwise.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Will Nicholes, Prime Signatures

Index entries for sequences related to prime signature

Formula

a(n) = A056170(A025487(n)).

Example

The canonical prime factorization of 24 (2^3*3) has 1 exponent that equals or exceeds 2. Since 24 = A025487(8), a(8) = 1.

Crossrefs

Cf. A025487, A212172.

Sequence in context: A161098 A354999 A136177 * A322818 A362611 A374470

Adjacent sequences: A212175 A212176 A212177 * A212179 A212180 A212181

Keyword

nonn

Author

Matthew Vandermast, Jun 04 2012

Status

approved