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A291211 Numbers k>1 such that k*k^(1/k) is closer to an integer than for any smaller number. 2

%I #14 Aug 22 2017 20:16:14

%S 2,5,6,15,16,46,135,136,385,1072,21976,59813,59814,162682,162683,

%T 442329,1202506,3268905,24154808,65659807,485164995,1318815513,

%U 1318815514,26489121842,72004899025,195729609091,532048240237,1446257063899

%N Numbers k>1 such that k*k^(1/k) is closer to an integer than for any smaller number.

%C The corresponding closest matching integers are given in A291212.

%e Let s(x) = x*x^(1/x), r(x) = round(s(x)), d(x) = abs(s(x)-r(x));

%e a(1) = 2:

%e s(2) = 2.8284271...,

%e r(2) = A291212(1) = 3,

%e d(2) = 0.17157...;

%e a(2) = 5:

%e s(5) = 6.8986483...,

%e r(5) = A291212(2) = 7,

%e d(5) = 0.10135169...;

%e a(3) = 6:

%e s(6) = 8.0880369...,

%e r(6) = A291212(3) = 8,

%e d(6) = 0.08803692...;

%e a(4) = 15:

%e s(15) = 17.96790087...,

%e r(15) = A291212(4) = 18,

%e d(18) = 0.03209912...;

%e a(5) = 16:

%e s(16) = 19.02731384...,

%e r(16) = A291212(5) = 19,

%e d(19) = 0.02731384...;

%Y Cf. A291210, A291212.

%K nonn

%O 1,1

%A _Hugo Pfoertner_, Aug 21 2017

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