A098385 Ordered factorizations over hook-type prime signatures with exactly three distinct primes (third column of A098348).

13, 44, 132, 368, 976, 2496, 6208, 15104, 36096, 84992, 197632, 454656, 1036288, 2342912, 5259264, 11730944, 26017792, 57409536, 126091264, 275775488, 600834048, 1304428544, 2822766592, 6090129408, 13103005696, 28118614016, 60196651008

Offset

0,1

Comments

a(n) can also be calculated by transforming (3,18,8) applying the binomial transform twice. Cf. A098384.

Links

James Rayman, Table of n, a(n) for n = 0..2000

Formula

a(n) = 2^n * (n^2 + 8*n + 13). - James Rayman, Mar 27 2021

Example

The hook-type least prime signatures with exactly three primes begin 30,60,120,...; therefore sequence begins A002033(30,60,120,...) = 13,44,132,...

Prog

(Python) def a(n): return 2**n * (n**2 + 8*n + 13) # James Rayman, Mar 27 2021

Crossrefs

Cf. A002033, A098348, A098384.

Sequence in context: A026914 A226514 A159742 * A048364 A254675 A141549

Adjacent sequences: A098382 A098383 A098384 * A098386 A098387 A098388

Keyword

easy,nonn

Author

Alford Arnold, Sep 06 2004

Extensions

More terms from James Rayman, Mar 27 2021

Status

approved