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Powers of fifth root of 15 rounded to nearest integer.
1

%I #19 Jul 01 2024 17:02:53

%S 1,2,3,5,9,15,26,44,76,131,225,387,665,1142,1964,3375,5801,9970,17137,

%T 29454,50625,87013,149555,257051,441813,759375,1305192,2243328,

%U 3855769,6627188,11390625,19577886,33649922

%N Powers of fifth root of 15 rounded to nearest integer.

%H Paolo Xausa, <a href="/A018157/b018157.txt">Table of n, a(n) for n = 0..1000</a>

%t Round[(15^(1/5))^Range[0, 50]] (* _Paolo Xausa_, Jul 01 2024 *)

%o (Python)

%o from gmpy2 import iroot_rem

%o def A018157(n):

%o i, j = iroot_rem(15**n,5)

%o return int(i)+int(j<<5>=10*i*((i*((i*(i+1)<<1)+1)<<2)+1)+1) # _Chai Wah Wu_, Jun 20 2024

%Y Cf. A011100.

%K nonn

%O 0,2

%A _N. J. A. Sloane_