A215737 a(n) is the first digit to appear n times in succession in a power of 11.

1, 1, 8, 7, 6, 0, 6, 0, 9, 6, 6, 2, 2, 7, 6, 9

Offset: 1

Author

V. Raman, Aug 22 2012

Keywords

• nonn
• more
• base

Crossrefs

Cf. A001020 (powers of 11), A045875, A215731, A215732.

Programs

Mathematica

n = 1; x = 1; lst = {};
For[i = 1, i <= 10000, i++,
z = Split[IntegerDigits[x]]; a = Length /@ z; b = Max[a];
For[j = n, j <= b, j++,
  AppendTo[lst, First[First[Part[z, First[Position[a, b]]]]]]; n++
]; x = 11 x ]; lst  (* Robert Price, Mar 16 2019 *)

Python

def A215737(n):
    a, s = 1, tuple(str(i)*n for i in range(10))
    while True:
        a *= 11
        t = str(a)
        for i, x in enumerate(s):
            if x in t:
                return i # Chai Wah Wu, Mar 30 2021

Extensions

a(10)-a(13) added by V. Raman, Apr 30 2012, in correspondence with A215731.

a(14) from Giovanni Resta, Apr 18 2016

a(15) from Bert Dobbelaere, Feb 15 2019

a(16) from Paul Geneau de Lamarlière, Oct 03 2024