A297829 Duplicates in A297826.

51, 59, 243, 279, 287, 295, 363, 371, 422, 430, 538, 587, 684, 872, 934, 1075, 1083, 1091, 1232, 1268, 1304, 1312, 1320, 1388, 1396, 1515, 1598, 1634, 1642, 1650, 1718, 1726, 1855, 1891, 1899, 1907, 1975, 1983, 2034, 2042, 2093, 2101, 2209, 2258, 2355, 2363

Offset: 1

Author

Clark Kimberling, Feb 04 2018

Keywords

• nonn
• easy

Crossrefs

Cf. A297826.

Programs

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]];
du = Differences[Table[a[n], {n, 0, 1000}]]  (* A297827 *)
w = Flatten[Position[du, 0]]; Map[a, w] (* A297829 *)