

A063543


a(n) = n  product of nonzero digits of n.


6



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
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OFFSET

1,10


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).


EXAMPLE

a(20) = 20  2 = 18.


MAPLE

a:= n> nmul(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) ProdNzD(x)= { local(d, p); p=1; while (x>9, d=x10*(x\10); if (d, p*=d); x\=10); return(p*x) }
{ for (n=1, 2000, write("b063543.txt", n, " ", n  ProdNzD(n)) ) } \\ Harry J. Smith, Aug 25 2009
(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. 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



