This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A086351 #10 Dec 05 2022 11:45:51 %S A086351 1,4,17,74,325,1432,6317,27878,123049,543148,2397545,10583234, %T A086351 46716589,206216896,910285253,4018193246,17737162705,78295623508, %U A086351 345613602113,1525612248122,6734378273941,29726983906792,131221255523165 %N A086351 T(n,3) of A086350. %C A086351 Binomial transform of A007052. Second binomial transform of Pell numbers A000129 (without leading zero). %H A086351 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-7). %F A086351 G.f.: (1-2x)/(1-6x+7x^2); %F A086351 a(n)=((1+sqrt(2))(3+sqrt(2))^n-(1-sqrt(2))(3-sqrt(2))^n)/(sqrt(8)). %F A086351 a(n) = A081179(n+1)-2*A081179(n). - _R. J. Mathar_, Dec 05 2022 %o A086351 (PARI) a(n)=my(sqrt2=quadgen(8)); simplify(((1+sqrt2)*(3+sqrt2)^n-(1-sqrt2)*(3-sqrt2)^n)/sqrt2^3) \\ _Charles R Greathouse IV_, Oct 24 2014 %K A086351 easy,nonn %O A086351 0,2 %A A086351 _Paul Barry_, Jul 18 2003