A131545 Least k such that 3^k has exactly n consecutive 8's in its decimal representation.

4, 23, 32, 215, 1261, 538, 4797, 17612, 32311, 375482, 512959, 1847532, 8295710, 8885853, 80798025

Offset

1,1

Comments

No more terms < 10^8. - Bert Dobbelaere, Mar 20 2019

Links

Table of n, a(n) for n=1..15.

Example

a(3)=32 because 3^32 (i.e., 1853020188851841) is the smallest power of 3 to contain a run of 3 consecutive eights in its decimal form.

Mathematica

a = ""; Do[ a = StringJoin[a, "8"]; b = StringJoin[a, "8"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]

Crossrefs

Cf. A195269, A131552, A131551, A131550, A131549, A131548, A131547, A131546, A131544.

Sequence in context: A258203 A293698 A160613 * A030716 A169599 A106684

Adjacent sequences: A131542 A131543 A131544 * A131546 A131547 A131548

Keyword

more,nonn,base

Author

Shyam Sunder Gupta, Aug 26 2007

Extensions

a(11)-a(14) from Lars Blomberg, Feb 02 2013

a(15) from Bert Dobbelaere, Mar 20 2019

Status

approved