A215736 a(n) is the first digit to appear n times in succession in a power of 7.

1, 1, 7, 9, 5, 7, 3, 1, 0, 0, 3, 4, 6, 5, 9, 1

Offset: 1

Author

V. Raman, Aug 22 2012

Keywords

• nonn
• base
• hard
• more

Crossrefs

Cf. A215730, A045875, 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 = 7 x ]; lst (* Robert Price, Mar 16 2019 *)

Extensions

a(10) added by V. Raman, Nov 23 2013

a(11)-a(13) from Giovanni Resta, Apr 19 2016

a(14)-a(15) from Bert Dobbelaere, Feb 15 2019

a(16) from Paul Geneau de Lamarlière, Jul 16 2024