OFFSET
1,3
COMMENTS
Extended to a(1)-a(2) using the formula.
LINKS
Eric Weisstein's World of Mathematics, Harary Index
EXAMPLE
0, 1, 3, 5, 15/2, 10, 77/6, 47/3, 75/4, 131/6, ...
MATHEMATICA
Numerator[Table[1 - Mod[n, 2] + n HarmonicNumber[Floor[(n - 1)/2]], {n, 20}]] (* Eric W. Weisstein, Dec 06 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Apr 30 2009
STATUS
approved