A296843 Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n+1), where a(0) = 1, a(1) = 2, b(0) = 3, b(1) = 4, b(2) = 5, b(3) = 6, and (a(n)) and (b(n)) are increasing complementary sequences.
1, 2, 9, 18, 35, 63, 109, 184, 306, 504, 825, 1345, 2187, 3551, 5758, 9330, 15110, 24463, 39597, 64085, 103708, 167820, 271556, 439405, 710991, 1150427, 1861450, 3011910, 4873394, 7885340, 12758771, 20644149, 33402959, 54047148, 87450148, 141497338
Offset: 0
Examples
a(0) = 1, a(1) = 2, b(0) = 3, b(1) = 4, b(2) = 5, b(3) = 6 a(2) = a(0) + a(1) + b(3) = 9 Complement: (b(n)) = (3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, ...)
Links
- Clark Kimberling, Table of n, a(n) for n = 0..1000
- Clark Kimberling, Complementary equations, J. Int. Seq. 19 (2007), 1-13.
Programs
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Mathematica
a[0] = 1; a[1] = 2; b[0] = 3; b[1] = 4; b[2] = 5; b[3] = 6; a[n_] := a[n] = a[n - 1] + a[n - 2] + b[n + 1]; j = 1; While[j < 16, k = a[j] - j - 1; While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++]; u = Table[a[n], {n, 0, k}]; (* A296843 *) Table[b[n], {n, 0, 20}] (* complement *)
Comments