A063543 a(n) = n - product of the nonzero digits of n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 18, 19, 18, 17, 16, 15, 14, 13, 12, 11, 27, 28, 26, 24, 22, 20, 18, 16, 14, 12, 36, 37, 34, 31, 28, 25, 22, 19, 16, 13, 45, 46, 42, 38, 34, 30, 26, 22, 18, 14, 54, 55, 50, 45, 40, 35, 30, 25, 20, 15, 63, 64, 58

Offset

1,10

Comments

The graph somewhat resembles wisteria flowers.

Links

Harry J. Smith, Table of n, a(n) for n = 1..2000

N. J. A. Sloane and Brady Haran, Amazing Graphs II (including Star Wars), Numberphile video (2019).

Formula

a(n) = n - A051801(n).

Example

a(20) = 20 - 2 = 18.

Maple

a:= n-> n-mul(i, i=subs(0=1, convert(n, base, 10))):
seq(a(n), n=1..80);  # Alois P. Heinz, Aug 18 2019

Mathematica

Table[n - Times@@DeleteCases[IntegerDigits[n], 0], {n, 70}] (* Alonso del Arte, Dec 15 2013 *)

Prog

(PARI) a(n) = my(d=select(x->(x!=0), digits(n))); n - vecprod(d); \\ Michel Marcus, Jan 13 2020
(Python)
def a(n):
    digits = map(int, str(n))
    product = 1
    for d in digits:
        if d != 0:
            product *= d
    return n - product
[a(n) for n in range(20)]
# Elisabeth Zemack, Sep 16 2019; corrected by Fabio Somenzi, Jan 13 2020
(Magma) [n - &*[a: k in [1..#Intseq(n)] | a ne 0 where a is Intseq(n)[k]]: n in [1..100]]; // Marius A. Burtea, Sep 16 2019

Crossrefs

Cf. A051801, A063114.

Sequence in context: A158001 A157763 A010735 * A096166 A240919 A078548

Adjacent sequences: A063540 A063541 A063542 * A063544 A063545 A063546

Keyword

nonn,base,easy,look

Author

N. J. A. Sloane, Aug 14 2001

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Aug 14 2001

Status

approved