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

Author

Shyam Sunder Gupta, Aug 26 2007

Keywords

• more
• nonn
• base

Comments

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

Examples

			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.
		

Crossrefs

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

Programs

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} ]

Extensions

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

a(15) from Bert Dobbelaere, Mar 20 2019