A147601 First differences of A132355.
7, 4, 21, 8, 35, 12, 49, 16, 63, 20, 77, 24, 91, 28, 105, 32, 119, 36, 133, 40, 147, 44, 161, 48, 175, 52, 189, 56, 203, 60, 217, 64, 231, 68, 245, 72, 259, 76, 273, 80, 287, 84, 301, 88, 315, 92, 329, 96, 343, 100, 357
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).
Programs
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Magma
[(9 + 5*(-1)^n)*(1+n)/2: n in [0..60]]; // G. C. Greubel, Oct 25 2022
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Mathematica
Differences[Sort[Table[9n^2+2n,{n,-30,30}]]] (* or *) LinearRecurrence[ {0,2,0,-1},{7,4,21,8},60] (* Harvey P. Dale, Jun 04 2017 *) -
SageMath
[(9 + 5*(-1)^n)*(1+n)/2 for n in range(61)] # G. C. Greubel, Oct 25 2022
Formula
G.f.: ( 7+4*x+7*x^2 ) / ((1-x)*(1+x))^2. - R. J. Mathar, Jun 21 2011
a(2*n) = A147587(n).
a(2*n+1) = 4*(n+1).
a(n) = (9 + 5*(-1)^n)*(1+n)/2. - Colin Barker, Jun 06 2012
E.g.f.: (1/2)*(5*(1-x)*exp(-x) + 9*(1+x)*exp(x)). - G. C. Greubel, Oct 25 2022