A254447 a(n) is the smallest nonnegative integer such that a(n)! contains a string of exactly n consecutive 2's.

0, 2, 13, 31, 45, 200, 854, 3358, 4698, 29324, 55295, 263489, 567993, 2328803

Offset

0,2

Comments

a(n) > 10^7 for n >= 14. - Bert Dobbelaere, Oct 29 2018

Links

Table of n, a(n) for n=0..13.

Example

a(0) = 0 since 0! equals 1, which does not contain any '2'.
For n = 1, a(1) = 2 as 2! = 2 contains '2'.
For n = 2, a(2) = 13 as 13! = 6227020800 contains '22' and 13 is the smallest integer for which the condition is met.

Mathematica

A254447[n_] := Module[{m = 0},
   If[n == 0, While[MemberQ[IntegerDigits[m!], 2], m++]; m,
    t = Table[2, n];
    While[! MemberQ[Split[IntegerDigits[m!]], t], m++]; m]];
Table[A254447[n], {n, 0, 13}](* Robert Price, Mar 20 2019 *)

Crossrefs

Cf. A254042, A254448, A254449, A254500, A254501, A254502, A254716, A254717.

Sequence in context: A132602 A359125 A001914 * A031392 A156980 A158720

Adjacent sequences: A254444 A254445 A254446 * A254448 A254449 A254450

Keyword

nonn,base,more

Author

Martin Y. Champel, Jan 30 2015

Extensions

a(11), a(12) from Jon E. Schoenfield, Feb 22 2015, Feb 27 2015

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

a(13) from Bert Dobbelaere, Oct 29 2018

Status

approved