OFFSET
1,1
COMMENTS
FORMULA
a(n) = floor(r*n), where r = 4 + sqrt(10).
MATHEMATICA
PROG
(Python)
from sympy import integer_nthroot
def A187395(n): return 4*n+integer_nthroot(10*n**2, 2)[0] # Chai Wah Wu, Mar 16 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 09 2011
EXTENSIONS
Edited by Clark Kimberling, Mar 17 2021
STATUS
approved