A254502 a(n) is the smallest nonnegative integer such that a(n)! contains a string of exactly n consecutive 7's.

0, 6, 31, 48, 22, 599, 1102, 5280, 4667, 1753, 48861, 150336, 223254, 644487, 7016773, 9588848

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Example

a(1) = 6 since 6! equals 720, which contains '7'.

Mathematica

A254452[n_] := Module[{m = 0},
   If[n == 0, While[MemberQ[IntegerDigits[m!], 7], m++]; m,
    t = Table[7, n];
    While[! MemberQ[Split[IntegerDigits[m!]], t], m++]; m]];
Table[A254452[n], {n, 0, 14}] (* Robert Price, Mar 21 2019 *)

Crossrefs

Cf. A254042, A254447, A254448, A254449, A254500, A254501, A254716, A254717.

Sequence in context: A043058 A155097 A306331 * A025524 A042841 A215730

Adjacent sequences: A254499 A254500 A254501 * A254503 A254504 A254505

Keyword

nonn,base,more

Author

Martin Y. Champel, Jan 31 2015

Extensions

a(11), a(12) from Jon E. Schoenfield, Feb 21 2015

a(0) prepended by Jon E. Schoenfield, Mar 01 2015

a(13) from Jon E. Schoenfield, Mar 06 2015

a(14)-a(15) from Bert Dobbelaere, Oct 29 2018

Status

approved