login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A329390
Solution sequence (a(n)) of the complementary equation a(n) = 6 b(n+1) - 2 b(n), with b(0) = 1.
4
10, 14, 18, 22, 26, 30, 34, 38, 48, 50, 54, 64, 66, 70, 80, 82, 86, 96, 98, 102, 112, 114, 118, 128, 130, 134, 144, 146, 150, 160, 162, 166, 170, 174, 178, 182, 186, 190, 200, 208, 210, 214, 224, 226, 230, 234, 238, 242, 246, 250, 254, 264, 272, 274, 278
OFFSET
0,1
COMMENTS
The conditions that (a(n)) and (b(n)) be increasing and complementary force the equation a(n) = 6 b(n+1) - 2 b(n), with initial value b(0) = 1, to have a unique solution; that is, a pair of complementary sequences (a(n)) = (10,14,18,22,26,30,34,...) and (b(n)) = (1,2,3,4,5,6,7,8,9,11,12,...). Conjecture: {a(n) - 5 n} is unbounded below and above.
EXAMPLE
(See A329387.)
MATHEMATICA
mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
b = {1}; a = {}; h = 6; k=2;
Do[AppendTo[b, mex[Flatten[{a, b}], b[[-1]]]];
AppendTo[a, h b[[-1]] - k b[[-2]]], {250}]; a
(* Peter J. C. Moses, Sep 07 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Nov 23 2019
STATUS
approved