A043281 Maximal run length in base-7 representation of n.

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 3, 2, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Links

• Winston de Greef, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007093 (base 7).

Cf. A043276-A043290 for base-2 to base-16 analogs.

Programs

Mathematica

Max[Length/@Split[IntegerDigits[#,7]]]&/@Range[100] (* Harvey P. Dale, Mar 30 2016 *)

PARI

A043281(n, b=7)={my(m,c=1); while(n>0, n%b==(n\=b)%b&&c++&&next; m=max(m, c); c=1); m} \\ M. F. Hasler, Jul 23 2013

Python

from itertools import groupby
from sympy.ntheory.factor_ import digits
def A043281(n): return max(len(list(g)) for k, g in groupby(digits(n,7)[1:])) # Chai Wah Wu, Mar 09 2023