A068001 Smallest number whose n-th power (A067457) starts with n.

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

Offset

1,2

Links

Paolo P. Lava, Table of n, a(n) for n = 1..500

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

Cf. A051248, A067457.

Sequence in context: A197491 A338595 A254274 * A213443 A302980 A242963

Adjacent sequences: A067998 A067999 A068000 * A068002 A068003 A068004

Keyword

base,easy,nonn

Author

Robert G. Wilson v, Feb 08 2002

Status

approved