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A217192 a(n) is the number of digits in the decimal representation of the smallest Lucas number that contains n consecutive identical digits. 1
1, 2, 8, 17, 24, 113, 657, 1346, 3667, 17318, 68642 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Number of digits in Lucas(k) is equal to floor(1 + k*log_10((1+sqrt(5))/2)).

LINKS

Table of n, a(n) for n=1..11.

MATHEMATICA

k = 0; Join[{1}, Table[While[d = IntegerDigits[LucasL[k]]; ! MemberQ[Partition[Differences[d], n - 1, 1], Table[0, {n - 1}]], k++]; Length[d], {n, 2, 8}]] (* T. D. Noe, Oct 02 2012 *)

PROG

(Python)

def A217192(n):

....if n == 1:

........return 1

....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 len(s)

............y, x = x, y+x

........return 'search limit reached'

# Chai Wah Wu, Dec 17 2014

CROSSREFS

Cf. A000032, A217166, A217176.

Sequence in context: A192155 A131362 A284395 * A224865 A192159 A066564

Adjacent sequences:  A217189 A217190 A217191 * A217193 A217194 A217195

KEYWORD

nonn,base,hard

AUTHOR

V. Raman, Sep 27 2012

EXTENSIONS

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

STATUS

approved

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Last modified December 5 03:33 EST 2021. Contains 349530 sequences. (Running on oeis4.)