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A296265
Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-2)*b(n-1), where a(0) = 3, a(1) = 4, b(0) = 1, b(1) = 2, and (a(n)) and (b(n)) are increasing complementary sequences.
2
3, 4, 9, 23, 62, 127, 245, 452, 807, 1391, 2354, 3927, 6491, 10658, 17421, 28385, 46148, 74913, 121481, 196856, 318865, 516321, 835836, 1352859, 2189451, 3543122, 5733443, 9277495, 15011930, 24290481, 39303533, 63595204, 102899997, 166496533, 269397936
OFFSET
0,1
COMMENTS
The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values. a(n)/a(n-1) -> (1 + sqrt(5))/2 = golden ratio (A001622). See A296245 for a guide to related sequences.
LINKS
Clark Kimberling, Complementary equations, J. Int. Seq. 19 (2007), 1-13.
EXAMPLE
a(0) = 3, a(1) = 4, b(0) = 2, b(1) = 1, b(2) = 2;
a(2) = a(0) + a(1) + b(0)*b(1) = 9;
Complement: (b(n)) = (1, 2, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, ...)
MATHEMATICA
a[0] = 3; a[1] = 4; b[0] = 1; b[1] = 2;
a[n_] := a[n] = a[n - 1] + a[n - 2] + b[n - 1] b[n - 2];
j = 1; While[j < 10, k = a[j] - j - 1;
While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++];
Table[a[n], {n, 0, k}]; (* A296265 *)
Table[b[n], {n, 0, 20}] (* complement *)
CROSSREFS
Sequence in context: A032789 A299123 A245455 * A034921 A038222 A038629
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Dec 12 2017
STATUS
approved