A097328 Denominator of 1 + 1/5 + 1/9 +...+ 1/(4n+1).

1, 5, 45, 585, 9945, 69615, 348075, 10094175, 111035925, 4108329225, 168441498225, 56147166075, 393030162525, 20830598613825, 395781373662675, 24142663793423175, 24142663793423175, 555281267248733025

Offset: 0

Author

T. D. Noe, Aug 04 2004

Keywords

• easy
• frac
• nonn

Comments

The first 11 terms are the same as the least common multiples in A051539.

Crossrefs

Cf. A016813 (4n+1), A075136 (numerators), A051539 (lcm of 5, 9, 13, ..., 4n+1).

Programs

Mathematica

Table[Denominator[Total[1/Range[1, 4n+1, 4]]], {n, 0, 20}]