login
A330989
Least positive integer with exactly 2^n factorizations into factors > 1, or 0 if no such integer exists.
11
1, 4, 12, 0, 72, 0, 480
OFFSET
0,2
EXAMPLE
The A001055(n) factorizations for n = 1, 4, 12, 72:
() (4) (12) (72)
(2*2) (2*6) (8*9)
(3*4) (2*36)
(2*2*3) (3*24)
(4*18)
(6*12)
(2*4*9)
(2*6*6)
(3*3*8)
(3*4*6)
(2*2*18)
(2*3*12)
(2*2*2*9)
(2*2*3*6)
(2*3*3*4)
(2*2*2*3*3)
CROSSREFS
All nonzero terms belong to A025487 and also A033833.
Factorizations are A001055, with image A045782.
The least number with exactly n factorizations is A330973(n).
Numbers whose number of factorizations is a power of 2 are A330977.
The least number with exactly prime(n) factorizations is A330992(n).
Sequence in context: A014458 A099733 A350259 * A073902 A144207 A016487
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jan 07 2020
STATUS
approved