A099552 a(n) is the smallest positive integer such that the concatenation of the first n terms is divisible by n.

1, 2, 3, 2, 5, 2, 5, 6, 1, 10, 2, 12, 5, 14, 5, 6, 8, 10, 15, 20, 7, 6, 18, 24, 25, 6, 32, 32, 3, 10, 1, 12, 41, 34, 5, 6, 8, 46, 33, 20, 34, 36, 21, 24, 30, 36, 36, 48, 23, 50, 56, 44, 34, 42, 30, 48, 9, 26, 4, 60, 44, 34, 33, 60, 65, 28, 16, 32, 66, 20, 29, 44, 78, 48, 75, 52, 9, 8, 37

Offset

1,2

Links

Paul Tek, Table of n, a(n) for n = 1..10000

Mathematica

spi[{ctn_, n_, a_}]:=Module[{k=1}, While[Mod[ctn*10^IntegerLength[k]+k, n+1] != 0, k++]; {ctn*10^IntegerLength[k]+k, n+1, k}]; NestList[spi, {1, 1, 1}, 80][[All, 3]] (* Harvey P. Dale, Nov 30 2022 *)

Prog

(PARI) num = 1; print(1); for (n = 2, 9, c = 10*num%n; d = n - c; print(d); num = 10*num + d); for (n = 10, 90, c = 10*num%n; d = n - c; if (d < 10, print(d); num = 10*num + d, c = 100*num%n; d = n - c; if (d < 10, d = d + n); print(d); num = 100*num + d));

Crossrefs

Cf. A051883, A073893, A083161, A100769.

Sequence in context: A328317 A088167 A073893 * A252749 A076199 A318057

Adjacent sequences: A099549 A099550 A099551 * A099553 A099554 A099555

Keyword

base,easy,nonn

Author

David Wasserman, Oct 21 2004

Status

approved