A225613 The largest n-digit number whose first k digits are divisible by the k-th prime for k = 1..n.

8, 87, 875, 8757, 87571, 875719, 8757193, 87571931, 875719319, 8757193191

Offset

1,1

Comments

There are 10 terms in the series; the 10-digit number 8757193191 is the largest number to satisfy the requirements.

Links

Table of n, a(n) for n=1..10.

Example

There are four one-digit numbers divisible by the first prime (2) and the largest is 8, so a(1)=8.
For two-digit numbers, the second digit must make it divisible by 3, which gives 87 as the largest to satisfy the requirement, so a(2)=87.

Mathematica

a=Table[j, {j, 2, 8, 2}]; r=2; t={}; While[!a == {}, n=Length[a]; nmax=Last[a]; k=1; b={}; While[!k>n, z0=a[[k]]; Do[z=10*z0+j; If[Mod[z, Prime[r]]==0, b=Append[b, z]], {j, 0, 9}]; k++]; AppendTo[t, nmax]; a=b; r++]; t

Crossrefs

Subsequence of A079206.

Cf. A143867, A225614.

Sequence in context: A200767 A222513 A307822 * A358982 A243922 A239753

Adjacent sequences: A225610 A225611 A225612 * A225614 A225615 A225616

Keyword

nonn,base,fini,full

Author

Shyam Sunder Gupta, Aug 04 2013

Status

approved