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%I #7 Mar 07 2022 02:06:25
%S 7,1,55,91,5,187,247,35,391,475,7,667,775,11,1015,1147,143,1435,1591,
%T 65,1927,2107,85,2491,2695,323,3127,3355,133,3835,4087,161,4615,4891,
%U 575,5467,5767,75,6391,6715,87,7387,7735,899,8455,8827,341,9595,9991,385,10807,11227,1295,12091,12535
%N Second bisection of A061039.
%C 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.
%H G. C. Greubel, <a href="/A144450/b144450.txt">Table of n, a(n) for n = 1..5000</a>
%H <a href="/index/Rec#order_81">Index entries for linear recurrences with constant coefficients</a>, 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).
%F a(n) = A061039(2*n+2).
%F a(n) = 3*a(n-27) - 3*a(n-54) + a(n-81). - _G. C. Greubel_, Mar 06 2022
%t Numerator[1/9 - 1/(2*Range[2, 100])^2] (* _G. C. Greubel_, Mar 06 2022 *)
%o (Sage) [numerator(1/9 -1/(2*n+2)^2) for n in (1..100)] # _G. C. Greubel_, Mar 06 2022
%Y Cf. A061039, A144448.
%K nonn
%O 1,1
%A _Paul Curtz_, Oct 06 2008
%E Formula index corrected, extended by _R. J. Mathar_, Dec 02 2008
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