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A049931
a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 4.
0
1, 3, 4, 5, 8, 18, 34, 55, 73, 198, 394, 775, 1513, 2883, 5189, 8270, 11153, 30573, 61144, 122275, 244513, 488883, 977189, 1952270, 3899153, 7776003, 15460304, 30554000, 59644613, 113465493, 204152989, 325394485, 438859978
OFFSET
1,2
MAPLE
s := proc(n) option remember; `if`(n < 1, 0, a(n) + s(n - 1)) end proc:
a := proc(n) option remember;
`if`(n < 4, [1, 3, 4][n], s(n - 1) - a(-2^ceil(log[2](n - 1)) + 2*n - 2)):
end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Apr 25 2020
CROSSREFS
Sequence in context: A219038 A258454 A176776 * A335436 A058983 A261208
KEYWORD
nonn
EXTENSIONS
Name edited by Petros Hadjicostas, Apr 25 2020
STATUS
approved