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A049854
a(n)=Sum{a(k): k=0,1,2,...,n-3,n-1}; a(n-2) is not a summand; 2 initial terms required.
0
1, 3, 3, 4, 8, 15, 26, 45, 79, 139, 244, 428, 751, 1318, 2313, 4059, 7123, 12500, 21936, 38495, 67554, 118549, 208039, 365083, 640676, 1124308, 1973023, 3462414, 6076113, 10662835, 18711971, 32837220, 57625304, 101125359
OFFSET
0,2
FORMULA
a(n)=2*a(n-1)-a(n-2)+a(n-3); 3 initial terms required.
MATHEMATICA
LinearRecurrence[{2, -1, 1}, {1, 3, 3}, 40] (* Harvey P. Dale, Jun 08 2022 *)
CROSSREFS
Sequence in context: A160646 A019466 A111573 * A353265 A366758 A291872
KEYWORD
nonn
STATUS
approved