A054028 a(n) = first k such that 2^k >= k^n, (for n >= 2, k >= 2).

2, 10, 16, 23, 30, 37, 44, 52, 59, 67, 75, 83, 92, 100, 109, 117, 126, 135, 144, 153, 162, 171, 180, 190, 199, 208, 218, 227, 237, 247, 256, 266, 276, 286, 296, 306, 316, 326, 336, 346, 356, 367, 377, 387, 398, 408, 418, 429, 439, 450, 460, 471, 482, 492

Offset

2,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 2..1000

Example

a(3) = 10 since 2^10=1024 >= 10^3=1000. a(4) = 16 since 2^16=65536 >= 16^4=65536.

Maple

Digits:= 500: f := k->2^x=x^k; seq(ceil(fsolve(f(n), x, 2..infinity)), n=2..20); # for n >= 2

Mathematica

f[n_]:=Module[{k=2}, While[2^k<k^n, k++]; k]; Join[{0, 0}, Array[f, 60, 2]] (* Harvey P. Dale, Jan 15 2012 *)

Prog

(Haskell)
a054028 n = head [k | k <- [2..], 2^k >= k^n] :: Integer
-- Reinhard Zumkeller, Jul 24 2013

Crossrefs

Cf. A000079, A054029.

Sequence in context: A307055 A060658 A239321 * A063716 A125212 A341060

Adjacent sequences: A054025 A054026 A054027 * A054029 A054030 A054031

Keyword

nonn,nice

Author

Asher Auel, Feb 28 2000

Status

approved