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 A179744 #14 Jul 14 2015 01:09:26 %S A179744 1,2,4,9,20,43,90,185,376,759,1526,3061,6132,12275,24562,49137,98288, %T A179744 196591,393198,786413,1572844,3145707,6291434,12582889,25165800, %U A179744 50331623,100663270,201326565,402653156,805306339,1610612706,3221225441 %N A179744 a(0) = 1, a(n) = 3*2^(n-1) - n for n>0. %C A179744 Equals row sums of triangle A179743. %C A179744 Essentially the same as A133095 and A123720. - _R. J. Mathar_, Jul 26 2010 %H A179744 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2). %F A179744 a(0) = 1, a(1) = 2; a(n) = 2*a(n-1) + (n-2) for n>1. %F A179744 G.f. 1-x*(2-4*x+3*x^2) / ( (2*x-1)*(x-1)^2 ). - _R. J. Mathar_, May 03 2013 %e A179744 a(5) = 43 = 2*a(4) + 3 = 2*20 + 3 %e A179744 a(5) = 43 = sum of row 5 terms, triangle A179743: (1 + 5 + 8 + 12 + 16 + 1). %t A179744 a[0] = 1; a[1] = 2; a[n_] := a[n] = 2 a[n - 1] + (n - 2); Array[a, 35, 0] (* _Robert G. Wilson v_, Aug 03 2010 *) %o A179744 (PARI) a(n)=3*2^n\2-n \\ _Charles R Greathouse IV_, May 03 2013 %Y A179744 Cf. A179743. %K A179744 nonn,easy %O A179744 0,2 %A A179744 _Gary W. Adamson_, Jul 25 2010 %E A179744 More terms from _Robert G. Wilson v_, Aug 03 2010