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A049932
a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.
0
1, 1, 1, 4, 8, 16, 32, 71, 166, 301, 602, 1211, 2446, 5026, 10488, 22820, 53682, 96877, 193754, 387515, 775054, 1550242, 3100920, 6203684, 12415410, 24874014, 49888100, 100357500, 203040866, 415396222, 868265134, 1889683034
OFFSET
1,4
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, 1, 1][n], s(n - 1) + a(-2^ceil(log[2](n - 1)) + 2*n - 3)):
end proc:
seq(a(n), n = 1..40); # Petros Hadjicostas, Nov 15 2019
CROSSREFS
Sequence in context: A328634 A089890 A338313 * A272712 A020161 A068890
KEYWORD
nonn
EXTENSIONS
Name edited by Petros Hadjicostas, Nov 15 2019
STATUS
approved