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%I #27 Jul 16 2022 07:30:48
%S 0,8,30,66,116,180,258,350,456,576,710,858,1020,1196,1386,1590,1808,
%T 2040,2286,2546,2820,3108,3410,3726,4056,4400,4758,5130,5516,5916,
%U 6330,6758,7200,7656,8126,8610,9108,9620,10146,10686,11240,11808,12390,12986,13596
%N a(n) = 7*n^2 + n.
%C First bisection of A219191. - _Bruno Berselli_, Nov 15 2012
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F a(n) = A000290(n)*7 + n = A033582(n) + n. - _Omar E. Pol_, Dec 22 2008
%F a(n) = a(n-1) + 14*n - 6 with n>0, a(0)=0. - _Vincenzo Librandi_, Nov 17 2010
%e From _Bruno Berselli_, Oct 27 2017: (Start)
%e After 0:
%e 8 = -(1) + (2+3+4).
%e 30 = -(1+2) + (3+4+5+6+7+8).
%e 66 = -(1+2+3) + (4+5+6+7+8+9+10+11+12).
%e 116 = -(1+2+3+4) + (5+6+7+8+9+10+11+12+13+14+15+16). (End)
%o (PARI) a(n)=7*n^2+n \\ _Charles R Greathouse IV_, Jun 17 2017
%Y Cf. A000290, A033582. - _Omar E. Pol_, Dec 22 2008
%K nonn,easy
%O 0,2
%A Evgeniy A. Chukhlomin (dkea(AT)yandex.ru), Feb 18 2004
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