# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a125202 Showing 1-1 of 1 %I A125202 #53 Apr 22 2024 06:25:58 %S A125202 -1,5,19,41,71,109,155,209,271,341,419,505,599,701,811,929,1055,1189, %T A125202 1331,1481,1639,1805,1979,2161,2351,2549,2755,2969,3191,3421,3659, %U A125202 3905,4159,4421,4691,4969,5255,5549,5851,6161,6479,6805,7139,7481,7831,8189,8555,8929,9311,9701,10099,10505,10919,11341 %N A125202 a(n) = 4*n^2 - 6*n + 1. %H A125202 Vincenzo Librandi, Table of n, a(n) for n = 1..10000 %H A125202 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). %F A125202 a(n) = A125199(n,n-1) for n>1. %F A125202 A003415(a(n)) = A017089(n-1). %F A125202 From _Arkadiusz Wesolowski_, Dec 25 2011: (Start) %F A125202 a(1) = -1, a(n) = a(n-1) + 8*n - 10. %F A125202 a(n) = 2*a(n-1) - a(n-2) + 8 with a(1) = -1 and a(2) = 5. %F A125202 G.f.: (1 - 4*x + 11*x^2)/(1 - x)^3. (End) %F A125202 a(n) = A002943(n-1) - 1. - _Arkadiusz Wesolowski_, Feb 15 2012 %F A125202 a(n) = A028387(2n-3), with A028387(-1) = -1. - _Vincenzo Librandi_, Oct 10 2013 %F A125202 E.g.f.: exp(x)*(1 - 2*x + 4*x^2). - _Stefano Spezia_, Oct 10 2022 %F A125202 Sum_{n>=1} 1/a(n) = sqrt(5)/10*(psi(1/4+sqrt(5)/4) - psi(1/4-sqrt(5)/4)) = -0.656213833... - _R. J. Mathar_, Apr 22 2024 %t A125202 f[a_]:=4*a^2-6*a+1; lst={};Do[AppendTo[lst,f[n]],{n,0,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jul 14 2009 *) %o A125202 (Magma) [4*n^2 - 6*n + 1: n in [1..60]]; // _Vincenzo Librandi_, Jul 11 2011 %o A125202 (PARI) a(n)=4*n^2-6*n+1 \\ _Charles R Greathouse IV_, Sep 28 2015 %Y A125202 Cf. A125199. %Y A125202 Cf. A003415, A017089. %Y A125202 Cf. A002939, A016789, A017041, A017485, A028387. %Y A125202 Cf. A002943, A028387. %K A125202 sign,easy %O A125202 1,2 %A A125202 _Reinhard Zumkeller_, Nov 24 2006 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE