OFFSET
1,2
FORMULA
a(n)=-1+sum(floor(j+j*r) : 1<=j<=n), where r=(1+sqrt(5))/2, the golden ratio.
MATHEMATICA
c[k_]:=-1+Sum[Floor[j+j*GoldenRatio], {j, 1, k}];
c=Table[c[k], {k, 1, 40}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Aug 15 2011
STATUS
approved