cp's OEIS Frontend

A049973 a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.

%I A049973 #15 Nov 16 2019 03:27:32
%S A049973 1,3,3,10,18,45,83,166,330,825,1567,3096,6165,12322,24637,49274,98546,
%T A049973 246365,468093,923871,1841585,3680101,7358673,14716604,29432713,
%U A049973 58865262,117730441,235460844,470921661,941843314,1883686621
%N A049973 a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.
%p A049973 s := proc(n) option remember; `if`(n < 1, 0, a(n) + s(n - 1)) end proc:
%p A049973 a := proc(n) option remember;
%p A049973 `if`(n < 4, [1, 3, 3][n], s(n - 1) + a(2^ceil(log[2](n - 1)) + 2 - n)):
%p A049973 end proc:
%p A049973 seq(a(n), n = 1..40); # _Petros Hadjicostas_, Nov 14 2019
%Y A049973 Cf. A049933, A049937, A049945.
%K A049973 nonn
%O A049973 1,2
%A A049973 _Clark Kimberling_
%E A049973 Name edited by _Petros Hadjicostas_, Nov 14 2019