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A227153 Product of nonzero digits of n in factorial base. 11
1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 4, 4, 3, 3, 3, 3, 6, 6, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 4, 4, 3, 3, 3, 3, 6, 6, 2, 2, 2, 2, 4, 4, 2, 2, 2, 2, 4, 4, 4, 4, 4, 4, 8, 8, 6, 6, 6, 6, 12, 12, 3, 3, 3, 3, 6, 6, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

a(0) = 1 as an empty product always gives 1.

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..5040

FORMULA

For all n, a(A227157(n)) = A208575(A227157(n)).

PROG

(GNU/MIT Scheme):

(define (A227153 n) (apply * (delete-matching-items (n->factbase n) zero?)))

(define (n->factbase n) (let loop ((n n) (fex (if (zero? n) (list 0) (list))) (i 2)) (cond ((zero? n) fex) (else (loop (floor->exact (/ n i)) (cons (modulo n i) fex) (1+ i))))))

(Python)

from operator import mul

def A(n, p=2):

    return n if n<p else A(n//p, p+1)*10 + n%p

def a(n):

    return 1 if n<2 else reduce(mul, [int(i) for i in str(A(n - 1)) if i!="0"])

print([a(n) for n in range(201)]) # Indranil Ghosh, Jun 19 2017

CROSSREFS

A227157 gives the positions where equal with A208575.

Cf. A007623, A227154, A227191.

Sequence in context: A328114 A343504 A328582 * A328581 A238643 A140193

Adjacent sequences:  A227150 A227151 A227152 * A227154 A227155 A227156

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Jul 04 2013

STATUS

approved

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Last modified May 16 10:58 EDT 2021. Contains 343941 sequences. (Running on oeis4.)