A225614 The smallest n-digit number whose first k digits are divisible by the k-th prime for k = 1..n.

2, 21, 210, 2100, 21076, 210769, 2107694, 21076947, 210769470, 6300846559

Offset

1,1

Comments

There are 10 terms in the series and the 10-digit number 6300846559 is the last 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 smallest is 2, so a(1)=2.
For two-digit numbers, the second digit must make it divisible by 3, which gives 21 as smallest to satisfy the requirement, so a(2)=21.

Mathematica

a=Table[j, {j, 2, 8, 2}]; r=2; t={}; While[!a == {}, n=Length[a]; nmin=First[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, nmin]; a=b; r++]; t

Crossrefs

Subsequence of A079206.

Cf. A143867, A225613.

Sequence in context: A077249 A068070 A085953 * A303500 A037527 A131584

Adjacent sequences: A225611 A225612 A225613 * A225615 A225616 A225617

Keyword

nonn,base,fini,full

Author

Shyam Sunder Gupta, Aug 04 2013

Status

approved