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A hierarchical sequence (S(W2{3}c) - see A059126).
1

%I #21 Jul 02 2023 16:08:59

%S 11,54,161,396,887,1890,3917,7992,16163,32526,65273,130788,261839,

%T 523962,1048229,2096784,4193915,8388198,16776785,33553980,67108391,

%U 134217234,268434941,536870376,1073741267,2147483070,4294966697,8589933972,17179868543,34359737706

%N A hierarchical sequence (S(W2{3}c) - see A059126).

%H Jonas Wallgren, <a href="/A059126/a059126.txt">Hierarchical sequences</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4, -5, 2).

%F Conjectures from _Colin Barker_, Oct 07 2015: (Start)

%F a(n) = -53 + 2^(6+n) - 21*n.

%F a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3) for n > 2.

%F G.f.: -(10*x+11) / ((x-1)^2*(2*x-1)).

%F (End)

%F a(n) = a(n-1) + Sum_{k=0..7*2^n-1} A059127(7*2^n-7+k) with a(-1)=0. - _Sean A. Irvine_, Sep 12 2022

%Y Cf. A059126, A059127.

%K nonn

%O 0,1

%A _Jonas Wallgren_, Jan 19 2001

%E More terms from _Sean A. Irvine_, Sep 12 2022