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%I #52 Feb 05 2023 16:28:45
%S 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,
%T 13,12,11,27,28,26,24,22,20,18,16,14,12,36,37,34,31,28,25,22,19,16,13,
%U 45,46,42,38,34,30,26,22,18,14,54,55,50,45,40,35,30,25,20,15,63,64,58
%N a(n) = n - product of nonzero digits of n.
%C The graph somewhat resembles wisteria flowers.
%H Harry J. Smith, <a href="/A063543/b063543.txt">Table of n, a(n) for n = 1..2000</a>
%H N. J. A. Sloane and Brady Haran, <a href="https://www.youtube.com/watch?v=o8c4uYnnNnc">Amazing Graphs II (including Star Wars)</a>, Numberphile video (2019).
%e a(20) = 20 - 2 = 18.
%p a:= n-> n-mul(i, i=subs(0=1, convert(n, base, 10))):
%p seq(a(n), n=1..80); # _Alois P. Heinz_, Aug 18 2019
%t Table[n - Times@@DeleteCases[IntegerDigits[n], 0], {n, 70}] (* _Alonso del Arte_, Dec 15 2013 *)
%o (PARI) ProdNzD(x)= { local(d,p); p=1; while (x>9, d=x-10*(x\10); if (d, p*=d); x\=10); return(p*x) }
%o { for (n=1, 2000, write("b063543.txt", n, " ", n - ProdNzD(n)) ) } \\ _Harry J. Smith_, Aug 25 2009
%o (PARI) a(n) = my(d=select(x->(x!=0), digits(n))); n - vecprod(d); \\ _Michel Marcus_, Jan 13 2020
%o (Python)
%o def a(n):
%o digits = map(int, str(n))
%o product = 1
%o for d in digits:
%o if d != 0:
%o product *= d
%o return n - product
%o [a(n) for n in range(20)]
%o # _Elisabeth Zemack_, Sep 16 2019; corrected by _Fabio Somenzi_, Jan 13 2020
%o (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
%Y Cf. A063114.
%K nonn,base,easy,look
%O 1,10
%A _N. J. A. Sloane_, Aug 14 2001
%E More terms from Larry Reeves (larryr(AT)acm.org), Aug 14 2001
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