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A068001 Smallest k such that its n-th power (A067457) starts with n. 1
1, 5, 7, 8, 9, 2, 5, 13, 46, 2, 19, 15, 6, 74, 12, 58, 4, 8, 5, 52, 6, 128, 85, 53, 15, 61, 113, 17, 55, 52, 83, 47, 147, 43, 297, 238, 63, 117, 51, 49, 145, 98, 219, 109, 48, 38, 114, 283, 423, 226, 334, 168, 38, 87, 91, 58, 189, 166, 42, 222, 92, 59, 133, 86, 544, 264, 5 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

EXAMPLE

a(3) = 7 because 7^3 = 343 which starts with 3 and there is no number less than 7 with this property.

MATHEMATICA

Do[k = Floor[ Log[ 10, n] + 1]; While[ FromDigits[ Take[ IntegerDigits [k^n], Floor[ Log[ 10, n] + 1]]] != n, k++ ]; Print[k^n], {n, 1, 100} ]

CROSSREFS

Sequence in context: A070366 A141606 A197491 * A191846 A068213 A065966

Adjacent sequences:  A067998 A067999 A068000 * A068002 A068003 A068004

KEYWORD

base,easy,nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 08 2002

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.