login
A017920
Powers of sqrt(5) rounded to nearest integer.
3
1, 2, 5, 11, 25, 56, 125, 280, 625, 1398, 3125, 6988, 15625, 34939, 78125, 174693, 390625, 873464, 1953125, 4367320, 9765625, 21836601, 48828125, 109183007, 244140625, 545915034, 1220703125, 2729575168
OFFSET
0,2
LINKS
MATHEMATICA
Floor[(Sqrt[5]^Range[0, 40]+1/2)] (* Vincenzo Librandi, Nov 19 2011 *)
PROG
(PARI) a(n)=round(sqrt(5)^n) \\ Charles R Greathouse IV, Nov 18 2011
(Magma) [Round(Sqrt(5)^n): n in [0..40]]; // Vincenzo Librandi, Nov 19 2011
(Python)
from math import isqrt
def A017920(n): return (m:=isqrt(k:=5**n))+(k-m*(m+1)>=1) # Chai Wah Wu, Jun 19 2024
CROSSREFS
Sequence in context: A192922 A215091 A017919 * A228765 A006054 A106805
KEYWORD
nonn
STATUS
approved