OFFSET
1
COMMENTS
See A187950.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
FORMULA
a(n)=[nr+5r]-[nr]-[5r], where r=(1+sqrt(5))/2.
MATHEMATICA
PROG
(Python)
from __future__ import division
from gmpy2 import isqrt
def A187946(n):
return int((isqrt(5*(n+5)**2)+n+1)//2 -(isqrt(5*n**2)+n)//2 - 6) # Chai Wah Wu, Oct 08 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 16 2011
STATUS
approved