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A217166
a(n) is the least value of k such that the decimal expansion of Lucas(k) contains n consecutive identical digits.
3
0, 5, 36, 78, 112, 538, 3139, 6436, 17544, 82864, 328448, 1701593, 1701593, 8030342, 8030342, 77552742
OFFSET
1,2
COMMENTS
a(12) > 1512000. - Chai Wah Wu, Dec 17 2014
a(17) > 10^8. - Nick Hobson, Feb 02 2024
MATHEMATICA
k = 0; Join[{0}, Table[While[d = IntegerDigits[LucasL[k]]; ! MemberQ[Partition[Differences[d], n - 1, 1], Table[0, {n - 1}]], k++]; k, {n, 2, 8}]] (* T. D. Noe, Oct 02 2012 *)
PROG
(Python)
def A217166(n):
....if n == 1:
........return 0
....else:
........l, y, x = [str(d)*n for d in range(10)], 2, 1
........for m in range(1, 10**9):
............s = str(x)
............for k in l:
................if k in s:
....................return m
............y, x = x, y+x
........return 'search limit reached'
# Chai Wah Wu, Dec 17 2014
(C) See Links section.
KEYWORD
nonn,base,hard
AUTHOR
V. Raman, Sep 27 2012
EXTENSIONS
a(11) from Chai Wah Wu, Dec 17 2014
a(12)-a(16) from Nick Hobson, Feb 02 2024
STATUS
approved