A217175 a(n) is the first digit (from the left) to appear n times in succession in the decimal representation of the Fibonacci(A217165(n)).

0, 5, 7, 7, 1, 5, 7, 7, 3, 2, 4, 3, 4, 2, 4

Offset: 1

Author

V. Raman, Sep 27 2012

Keywords

• nonn
• base
• hard

Crossrefs

Cf. A217165.

Cf. A000045, A215732, A215733, A215734, A215735, A215736, A215737.

Programs

Mathematica

k = 0; Join[{0}, Table[While[d = IntegerDigits[Fibonacci[k]]; prt = Partition[Differences[d], n - 1, 1]; ! MemberQ[prt, Table[0, {n - 1}]], k++]; d[[Position[prt, Table[0, {n - 1}]][[1, 1]]]], {n, 2, 8}]] (* T. D. Noe, Oct 03 2012 *)

Python

def A217175(n):
    if n == 1:
        return 0
    else:
        l, y, x = [str(d)*n for d in range(10)], 0, 1
        for m in range(1, 10**9):
            s = str(x)
            for k in range(10):
                if l[k] in s:
                    return k
            y, x = x, y+x
        return 'search limit reached'
# Chai Wah Wu, Dec 17 2014

Extensions

a(10)-a(11) from Chai Wah Wu, Dec 17 2014

a(12)-a(15) from Nick Hobson, Feb 14 2024