A144450 Second bisection of A061039.

7, 1, 55, 91, 5, 187, 247, 35, 391, 475, 7, 667, 775, 11, 1015, 1147, 143, 1435, 1591, 65, 1927, 2107, 85, 2491, 2695, 323, 3127, 3355, 133, 3835, 4087, 161, 4615, 4891, 575, 5467, 5767, 75, 6391, 6715, 87, 7387, 7735, 899, 8455, 8827, 341, 9595, 9991, 385, 10807, 11227, 1295, 12091, 12535

Offset: 1

Author

Paul Curtz, Oct 06 2008

Keywords

• nonn

Comments

Related to the Paschen spectrum of hydrogen. Contains only odd numbers. The sequence read modulo 9 is "full" and contains all numbers from 0 to 8.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000
• Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Crossrefs

Cf. A061039, A144448.

Programs

Mathematica

Numerator[1/9 - 1/(2*Range[2, 100])^2] (* G. C. Greubel, Mar 06 2022 *)

Sage

[numerator(1/9 -1/(2*n+2)^2) for n in (1..100)] # G. C. Greubel, Mar 06 2022

Formula

a(n) = A061039(2*n+2).

a(n) = 3*a(n-27) - 3*a(n-54) + a(n-81). - G. C. Greubel, Mar 06 2022

Extensions

Formula index corrected, extended by R. J. Mathar, Dec 02 2008