A242810 - OEIS

A242810

a(n) is the smallest n-digit number whose truncation after its first k digits is divisible by the k-th Lucas number (A000032(n)) for k = 1..n.

1, 12, 120, 1204, 12045, 120456, 3689467, 36894671, 368946712

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

There are 9 terms in the series and 9-digit number 368946712

is the last number to satisfy the requirements.

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

368946712 is divisible by Lucas(9) = 76;

36894671 is divisible by Lucas(8) = 47;

3689467 is divisible by Lucas(7) = 29;

368946 is divisible by Lucas(6) = 18;

36894 is divisible by Lucas(5) = 11;

3689 is divisible by Lucas(4) = 7;

368 is divisible by Lucas(3) = 4;

36 is divisible by Lucas(2) = 3;

3 is divisible by Lucas(1) = 1.

MATHEMATICA

a=Table[j, {j, 1, 10, 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, LucasL[r]]==0, b=Append[b, z]], {j, 0, 9}]; k++]; AppendTo[t, nmin]; a=b; r++]; t

CROSSREFS

Cf. A000032, A225614, A242808, A242809, A242811.

Sequence in context: A001754 A037511 A037694 * A067102 A361573 A129064

Adjacent sequences: A242807 A242808 A242809 * A242811 A242812 A242813

KEYWORD

nonn,base,fini,full

AUTHOR

Michel Lagneau, May 23 2014

STATUS

approved