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A049867 a(n) = Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; 3 initial terms required. 0
1, 1, 4, 5, 10, 17, 33, 61, 115, 214, 400, 746, 1393, 2600, 4854, 9061, 16915, 31576, 58945, 110036, 205411, 383453, 715815, 1336255, 2494468, 4656574, 8692708, 16227203, 30292300, 56548466, 105562437, 197059777, 367863388 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
a(n) = 2*a(n-1) - a(n-3) + a(n-4) for n >= 4.
G.f.: (1 - x + 2*x^2 - 2*x^3)/(1 - 2*x + x^3 - x^4). - Stefano Spezia, Dec 26 2021
CROSSREFS
Sequence in context: A285289 A022309 A049897 * A054173 A185875 A354080
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified March 1 18:30 EST 2024. Contains 370443 sequences. (Running on oeis4.)