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

Author

Martin Y. Champel, Jan 31 2015

Keywords

• nonn
• base
• more

Examples

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

Crossrefs

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

Programs

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 *)

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