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A297828 Difference sequence of A297997. 2
1, 1, 1, 2, 2, 2, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 3, 1, 1, 3, 1, 1, 1, 1, 2, 3, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 1, 1, 1, 2, 3, 2, 2, 2, 1, 1, 2, 1, 3, 2, 2, 2, 1, 1, 2, 1, 2, 1, 2, 1, 3, 2, 1, 1, 3, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Conjectures:

(1) 2 <= a(k) <= 4 for k>=1;

(2) if d is in {1,2,3}, then a(k) = d for infinitely many k.

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..10000

MATHEMATICA

mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);

tbl = {}; a[0] = 1; a[1] = 2; b[0] = 3; b[1] = 4;

a[n_] := a[n] = a[1]*b[n - 1] - a[0]*b[n - 2] + n;

b[n_] := b[n] = mex[tbl = Join[{a[n], a[n - 1], b[n - 1]}, tbl], b[n - 1]];

u = Table[a[n], {n, 0, 300}](* A297826 *)

v = Table[b[n], {n, 0, 300}](* A297997 *)

Differences[u];  (* A297827 *)

Differences[v];  (* A297828 *)

(* Peter J. C. Moses, Jan 03 2017 *)

CROSSREFS

Cf. A297826, A297827.

Sequence in context: A275333 A108393 A327342 * A062245 A062246 A037811

Adjacent sequences:  A297825 A297826 A297827 * A297829 A297830 A297831

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Feb 04 2018

STATUS

approved

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Last modified October 19 13:01 EDT 2019. Contains 328222 sequences. (Running on oeis4.)