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A243198 Least number k such that k + DigProd(k) = 10^n. 1
5, 91, 919, 7795, 100000, 1000000, 10000000, 100000000, 1000000000, 9968647168, 100000000000, 1000000000000, 9999761914432, 100000000000000, 1000000000000000, 10000000000000000, 100000000000000000, 1000000000000000000, 9999982446427242496 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) <= 10^n for all n.

LINKS

Hiroaki Yamanouchi, Table of n, a(n) for n = 1..50

EXAMPLE

919 + 9*1*9 = 1000 = 10^3. Since 919 is the smallest number with this property, a(3) = 919.

PROG

(PARI) DP(n)={p=1; d=digits(n); return(prod(i=1, #d, d[i]))}

a(n)=for(k=10^n-9^n, 10^n, if((k+DP(k))==10^n, return(k)))

n=1; while(n<100, print1(a(n), ", "); n++)

CROSSREFS

Cf. A007954, A242945.

Sequence in context: A282052 A152299 A242945 * A091281 A109625 A266290

Adjacent sequences:  A243195 A243196 A243197 * A243199 A243200 A243201

KEYWORD

nonn,base,hard

AUTHOR

Derek Orr, Jun 01 2014

EXTENSIONS

a(8)-a(19) from Hiroaki Yamanouchi, Jul 10 2014

STATUS

approved

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Last modified July 5 00:40 EDT 2020. Contains 335457 sequences. (Running on oeis4.)