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A018124
Powers of fifth root of 4 rounded to nearest integer.
1
1, 1, 2, 2, 3, 4, 5, 7, 9, 12, 16, 21, 28, 37, 49, 64, 84, 111, 147, 194, 256, 338, 446, 588, 776, 1024, 1351, 1783, 2353, 3104, 4096, 5405, 7132, 9410, 12417, 16384, 21619, 28526, 37641, 49667, 65536, 86475
OFFSET
0,3
PROG
(Python)
from gmpy2 import iroot_rem
def A018124(n):
i, j = iroot_rem(1<<(n<<1), 5)
return int(i)+int(j<<5>=10*i*((i*((i*(i+1)<<1)+1)<<2)+1)+1) # Chai Wah Wu, Jun 20 2024
CROSSREFS
Cf. A005533.
Sequence in context: A369571 A274200 A018052 * A133034 A124745 A000931
KEYWORD
nonn
AUTHOR
STATUS
approved