OFFSET
1,2
COMMENTS
LINKS
Jeff Bowermaster, Illustration of a(1)..a(3)
Jeff Bowermaster, Illustration of a(4) and a(5)
Jeff Bowermaster, Illustration of a(6)
Jeff Bowermaster, Illustration of a(7)
Jeff Bowermaster, Illustration of a(8)
FORMULA
For even n, a(n) = (n^2+4n)/2+3; for odd n, a(n) = (n^2+3n)/2+2 ; a(1) = 1.
PROG
(PARI) a(n) = if(n==1, 1, if(n%2, (n^2+3*n)/2+2, (n^2+4*n)/2+3))
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeff Bowermaster, Nov 11 2019
STATUS
approved