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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
OFFSET
1,2
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
KEYWORD
nonn,base,fini,full
AUTHOR
Derek Orr, Jul 07 2014
EXTENSIONS
a(7)-a(9) from Hiroaki Yamanouchi, Jul 10 2014
STATUS
approved