A372510 Number of ordered factorizations of 2*n-1 into twin primes.

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 0, 1, 1, 1, 1, 2, 2, 0, 2, 1, 1, 3, 0, 1, 2, 0, 2, 2, 1, 1, 3, 2, 0, 0, 1, 1, 3, 2, 0, 1, 0, 2, 2, 0, 2, 2, 2, 0, 3, 1, 1, 6, 1, 1, 0, 0, 0, 3, 2, 1, 2, 1, 0, 2, 0, 2, 4, 1, 1, 0, 2, 2, 3, 1, 1, 3, 2, 0, 0, 0, 0, 6, 0, 1, 3, 0, 3, 2, 1

Offset

1,8

Links

Table of n, a(n) for n=1..90.

Formula

If 2*n-1 = Product A001097(k)^e(k) then a(n) = A008480(2*n-1), otherwise 0.

Example

a(23) = 3 because we have 23 * 2 - 1 = 45 = 3 * 3 * 5 = 3 * 5 * 3 = 5 * 3 * 3.

Crossrefs

Cf. A001097, A008480, A050328, A050363, A062505, A077608, A164292.

Sequence in context: A355913 A373605 A025925 * A240857 A374318 A109066

Adjacent sequences: A372507 A372508 A372509 * A372511 A372512 A372513

Keyword

nonn

Author

Ilya Gutkovskiy, May 04 2024

Status

approved