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A131549 Least power of 3 having exactly n consecutive 4's in its decimal representation. 1
5, 12, 55, 308, 510, 2340, 7286, 9670, 125406, 222961 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

a(3)=55 because 3^55(i.e. 174449211009120179071170507) is the smallest power of 3 to contain a run of 3 consecutive fours in its decimal form.

MATHEMATICA

a = ""; Do[ a = StringJoin[a, "4"]; b = StringJoin[a, "4"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]

CROSSREFS

Sequence in context: A189421 A066961 A179994 * A111904 A015784 A129723

Adjacent sequences:  A131546 A131547 A131548 * A131550 A131551 A131552

KEYWORD

more,nonn,base

AUTHOR

Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 26 2007

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Last modified February 14 11:36 EST 2012. Contains 205623 sequences.