A092277 a(n) = 7*n^2 + n.
0, 8, 30, 66, 116, 180, 258, 350, 456, 576, 710, 858, 1020, 1196, 1386, 1590, 1808, 2040, 2286, 2546, 2820, 3108, 3410, 3726, 4056, 4400, 4758, 5130, 5516, 5916, 6330, 6758, 7200, 7656, 8126, 8610, 9108, 9620, 10146, 10686, 11240, 11808, 12390, 12986, 13596
Offset: 0
Examples
From _Bruno Berselli_, Oct 27 2017: (Start) After 0: 8 = -(1) + (2+3+4). 30 = -(1+2) + (3+4+5+6+7+8). 66 = -(1+2+3) + (4+5+6+7+8+9+10+11+12). 116 = -(1+2+3+4) + (5+6+7+8+9+10+11+12+13+14+15+16). (End)
Links
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Crossrefs
Programs
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PARI
a(n)=7*n^2+n \\ Charles R Greathouse IV, Jun 17 2017
Formula
a(n) = a(n-1) + 14*n - 6 with n > 0, a(0)=0. - Vincenzo Librandi, Nov 17 2010
From Elmo R. Oliveira, Nov 29 2024: (Start)
G.f.: 2*x*(4 + 3*x)/(1-x)^3.
E.g.f.: exp(x)*x*(8 + 7*x).
a(n) = 2*A022265(n).
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)
Comments