A098230 75-gonal numbers: a(n) = n*(73*n-71)/2.
0, 1, 75, 222, 442, 735, 1101, 1540, 2052, 2637, 3295, 4026, 4830, 5707, 6657, 7680, 8776, 9945, 11187, 12502, 13890, 15351, 16885, 18492, 20172, 21925, 23751, 25650, 27622, 29667, 31785, 33976, 36240, 38577, 40987, 43470, 46026, 48655, 51357, 54132, 56980, 59901, 62895, 65962, 69102, 72315, 75601, 78960, 82392, 85897, 89475
Offset: 0
Links
- Daniel Starodubtsev, Table of n, a(n) for n = 0..10000
- Index to sequences related to polygonal numbers
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Programs
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Magma
[ n*(73*n - 71)/2: n in [0..50] ]; // Vincenzo Librandi, Feb 04 2011
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Maple
A098230 := proc(n) n*(73*n-71)/2 ; end proc: seq(A098230(n),n=0..20) ; # R. J. Mathar, Feb 04 2011
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PARI
a(n)=n*(73*n-71)/2 \\ Charles R Greathouse IV, Oct 16 2015
Formula
G.f.: -x*(1+72*x) / (x-1)^3. - R. J. Mathar, Feb 05 2011
a(n) = n*(73*n - 71)/2.
E.g.f.: exp(x)*(x + 73*x^2/2). - Nikolaos Pantelidis, Feb 10 2023