A073911 Smallest number m such that m and the product of digits of m are both divisible by 5n, or 0 if no such number exists.

5, 0, 135, 0, 525, 0, 175, 0, 495, 0, 0, 0, 0, 0, 3525, 0, 0, 0, 0, 0, 735, 0, 0, 0, 55125, 0, 3915, 0, 0, 0, 0, 0, 0, 0, 1575, 0, 0, 0, 0, 0, 0, 0, 0, 0, 15975, 0, 0, 0, 37975, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9765, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 155625, 0, 0, 0, 0, 0, 31995, 0, 0

Offset

1,1

Comments

Here 0 is regarded as not divisible by any number.

a(n) = 0 if n is divisible by 2 or contains a prime divisor > 9. - Sascha Kurz, Aug 23 2002

Links

Table of n, a(n) for n=1..83.

Formula

a(n) = A085124(5*n). - R. J. Mathar, Jun 21 2018

Maple

f := 5:for i from 1 to 400 do b := ifactors(f*i)[2]: if b[nops(b)][1]>9 or (f*i mod 10) =0 then a[i] := 0:else j := 0:while true do j := j+f*i:c := convert(j, base, 10): d := product(c[k], k=1..nops(c)): if (d mod f*i)=0 and d>0 then a[i] := j:break:fi: od:fi:od:seq(a[k], k=1..400);

Crossrefs

Cf. A073906, A085124, A073908, A073909, A073910, A073912.

Sequence in context: A294314 A347599 A266324 * A157302 A275759 A222327

Adjacent sequences: A073908 A073909 A073910 * A073912 A073913 A073914

Keyword

nonn,base

Author

Amarnath Murthy, Aug 18 2002

Extensions

More terms from Sascha Kurz, Aug 23 2002

Status

approved