OFFSET
1,2
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
a(1)=0+1, excluding 0 and 1, so a(1)=0.
a(2)=0+1+2, excluding 0 and 1, so a(2)=2.
a(3)=0+1+2+3, excluding 0 and 1, so a(3)=2+3=5.
MAPLE
PROG
(PARI) g5(n)=for(x=1, n, r=floor(x^(1/5)); sum5=(2*r^6+6*r^5+5*r^4-r^2)/12; sn=x* (x+1)/2; print1(sn-sum5, ", "))
(PARI) a(n) = my(r=sqrtnint(n, 5)); n*(n+1)/2 - (2*r^6+6*r^5+5*r^4-r^2)/12; \\ Ruud H.G. van Tol, Nov 02 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Cino Hilliard, Nov 07 2007
EXTENSIONS
Edited by the Assoc. Editors of the OEIS, Oct 12 2010. Thanks to Daniel Mondot for pointing out that the sequence needed editing.
STATUS
approved