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A244852 Least number k > 0 such that 3^k begins with exactly n consecutive increasing digits. 3
1, 17, 149, 146, 7997, 45419, 3972963, 27487124, 406680034 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

3^17 = 129140163 begins with 2 consecutive increasing digits ('12'). Thus a(2) = 17.

PROG

(Python)

def a(n):

..for k in range(1, 10**5):

....st = str(3**k)

....count = 0

....if len(st) > n:

......for i in range(len(st)):

........if int(st[i]) == int(st[i+1])-1:

..........count += 1

........else:

..........break

......if count == n:

........return k

n = 0

while n < 10:

..print(a(n), end=', ')

..n += 1

CROSSREFS

Cf. A244848, A244849, A244851.

Sequence in context: A196780 A208506 A299599 * A064102 A161497 A162328

Adjacent sequences:  A244849 A244850 A244851 * A244853 A244854 A244855

KEYWORD

nonn,base,fini,full

AUTHOR

Derek Orr, Jul 07 2014

EXTENSIONS

a(7)-a(9) from Hiroaki Yamanouchi, Jul 10 2014

STATUS

approved

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Last modified May 12 01:50 EDT 2021. Contains 343808 sequences. (Running on oeis4.)