OFFSET
1,16
COMMENTS
LINKS
EXAMPLE
Of the eleven divisors of 220 larger than one, only [4, 10, 22, 55, 220] are in A340784, as both the number of their prime factors (with repetition, A001222), [2, 2, 2, 2, 4], and their integer pseudo logarithms (A056239), [2, 4, 6, 8, 10], are even. Using these factors gives the following possible factorizations: 220 = 22*10 = 55*4, therefore a(220) = 3.
Of the eight divisors of 256 larger than one, only [1, 4, 16, 64, 256] are in A340784. Using these factors, we obtain the following factorizations: 256 = 64*4 = 16*16 = 16*4*4 = 4*4*4*4, therefore a(256) = 5.
Of the 23 divisors of 792 larger than one, only [4, 9, 22, 36, 88, 198, 792] are in A340784. Using these factors gives the following possible factorizations: 792 = 198*4 = 88*9 = 36*22 = 22*4*9, therefore a(792) = 5.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 14 2022
STATUS
approved