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 A095768 #32 Mar 08 2025 15:34:33
%S A095768 3,6,13,28,59,122,249,504,1015,2038,4085,8180,16371,32754,65521,
%T A095768 131056,262127,524270,1048557,2097132,4194283,8388586,16777193,
%U A095768 33554408,67108839,134217702,268435429,536870884,1073741795,2147483618
%N A095768 a(n) = 2^(n+1) - n.
%C A095768 Least k such that valuation(A004001(k),2) = n.
%C A095768 Apart from initial term, row sums of triangle A135087.
%H A095768 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2).
%F A095768 From _R. J. Mathar_, Apr 30 2008: (Start)
%F A095768 O.g.f.: -x*(3-6*x+48*x^2)/((-1+x)^2*(-1+2*x)).
%F A095768 a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3). (End)
%F A095768 a(n) = A000247(n+1) + 3 = 2^(n+1) - n. - _Martin Ettl_, Nov 08 2012
%F A095768 E.g.f.: exp(x)*(2*exp(x) - x) - 2. - _Elmo R. Oliveira_, Mar 08 2025
%t A095768 Table[2^(n + 1) - n, {n, 0, 31}] (* _Robert G. Wilson v_ Jun 12 2004 *)
%t A095768 LinearRecurrence[{4,-5,2},{3,6,13},40] (* _Harvey P. Dale_, Jan 02 2012 *)
%o A095768 (Maxima) A095768(n):=2^(n+1)-n$
%o A095768 makelist(A095768(n),n,1,30); /* _Martin Ettl_, Nov 08 2012 */
%o A095768 (PARI) a(n)=2^(n+1)-n \\ _Charles R Greathouse IV_, Oct 16 2015
%Y A095768 Cf. A000247, A004001, A095767, A132045, A135087.
%K A095768 nonn,easy
%O A095768 1,1
%A A095768 _Benoit Cloitre_, Jun 05 2004