OFFSET
1,1
LINKS
Martin Y. Champel, Table of n, a(n) for n = 1..10000
EXAMPLE
for n=1, a(1)=4 as (1,0),(0,1),(-1,0),(0,-1) are powers of (1,0), (0,-1),(0,1) and (0,1) respectively powered by 2,3,2 and 3.
for n=2, a(2)=6 as in addition of the 4 previous points can be found 2 points (0,2) and (0,-2) built as (1,1)^2 and (1,-1)^2.
for n=3, a(3)=10 as in addition of the 6 previous points can be found 4 points (2,2), (2,-2), (-2,-2) and (-2,2) built as (-1,1)^3, (-1,-1)^3, (1,-1)^3 and (1,1)^3 respectively.
PROG
(Python)
from math import *
i0=complex(1, 0)
i1=complex(0, 1)
f0={0, i0, i1, -i0, -i1}
def A242877(n):
....if n==0: return 0
....if n==1: return 4
....f0={0, i0, i1, -i0, -i1}
....k=2
....while True:
........ro=n**(1/k)
........if ro<sqrt(1.9999):break
........ro_int = int(ro)
........for a in range(-ro_int, ro_int+1):
............b_max = int(sqrt(ro*ro-a*a))
............for b in range(-b_max, b_max+1):
................c=complex(a, b)
................f0.add(c**k)
........k+=1
....return len(f0)-1
CROSSREFS
KEYWORD
nonn
AUTHOR
Martin Y. Champel, May 25 2014
STATUS
approved