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A227191
a(n) = n minus (product of nonzero digits in factorial base representation of n).
5
0, 1, 2, 2, 3, 5, 6, 7, 8, 8, 9, 10, 11, 12, 13, 12, 13, 15, 16, 17, 18, 16, 17, 23, 24, 25, 26, 26, 27, 29, 30, 31, 32, 32, 33, 34, 35, 36, 37, 36, 37, 39, 40, 41, 42, 40, 41, 46, 47, 48, 49, 48, 49, 52, 53, 54, 55, 54, 55, 56, 57, 58, 59, 56, 57, 60, 61, 62
OFFSET
1,3
FORMULA
a(n) = n - A227153(n).
EXAMPLE
22 has factorial expansion A007623(22) = "320", and multiplying the nonzero digits, we get 3*2 = 6, and 22-6 = 16, thus a(22)=16.
MATHEMATICA
a[n_] := Module[{k = n, m = 2, r, p = 1}, While[{k, r} = QuotientRemainder[k, m]; k != 0|| r != 0, If[r > 0, p *= r]; m++]; n - p]; Array[a, 100] (* Amiram Eldar, Feb 14 2024 *)
PROG
(Scheme): (define (A227191 n) (- n (A227153 n)))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Jul 04 2013
STATUS
approved