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A262401 In prime factorization of n: replace each factor with its largest decimal digit. 4
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 12, 3, 14, 15, 16, 7, 18, 9, 20, 21, 2, 3, 24, 25, 6, 27, 28, 9, 30, 3, 32, 3, 14, 35, 36, 7, 18, 9, 40, 4, 42, 4, 4, 45, 6, 7, 48, 49, 50, 21, 12, 5, 54, 5, 56, 27, 18, 9, 60, 6, 6, 63, 64, 15, 6, 7, 28, 9, 70, 7, 72, 7, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = product(A054055(A027746(n,k)): k=1..A001222(n));

a(n) <= n;

a(m) = m iff m is 7-smooth: a(A002473(n)) = A002473(n) and a(A068191(n)) < A068191(n);

A006530(a(n)) <= 7;

a(a(n)) = a(n).

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

FORMULA

Multiplicative with p -> A054055(p), p prime.

PROG

(Haskell)

a262401 = product . map a054055 . a027746_row'

CROSSREFS

Cf. A054055, A027746, A001222, A002473, A006530, A060418, A068191.

Sequence in context: A067453 A203814 A280505 * A118541 A084905 A180409

Adjacent sequences:  A262398 A262399 A262400 * A262402 A262403 A262404

KEYWORD

nonn,base,mult

AUTHOR

Reinhard Zumkeller, Sep 25 2015

STATUS

approved

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Last modified May 9 13:42 EDT 2021. Contains 343742 sequences. (Running on oeis4.)