cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A018157 Powers of fifth root of 15 rounded to nearest integer.

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%I A018157 #19 Jul 01 2024 17:02:53
%S A018157 1,2,3,5,9,15,26,44,76,131,225,387,665,1142,1964,3375,5801,9970,17137,
%T A018157 29454,50625,87013,149555,257051,441813,759375,1305192,2243328,
%U A018157 3855769,6627188,11390625,19577886,33649922
%N A018157 Powers of fifth root of 15 rounded to nearest integer.
%H A018157 Paolo Xausa, <a href="/A018157/b018157.txt">Table of n, a(n) for n = 0..1000</a>
%t A018157 Round[(15^(1/5))^Range[0, 50]] (* _Paolo Xausa_, Jul 01 2024 *)
%o A018157 (Python)
%o A018157 from gmpy2 import iroot_rem
%o A018157 def A018157(n):
%o A018157     i, j = iroot_rem(15**n,5)
%o A018157     return int(i)+int(j<<5>=10*i*((i*((i*(i+1)<<1)+1)<<2)+1)+1) # _Chai Wah Wu_, Jun 20 2024
%Y A018157 Cf. A011100.
%K A018157 nonn
%O A018157 0,2
%A A018157 _N. J. A. Sloane_