A022935 a(n) = a(n-1) + c(n-1) for n >= 2, a( ) increasing, given a(1)=3, where c( ) is complement of a( ).

3, 4, 6, 11, 18, 26, 35, 45, 57, 70, 84, 99, 115, 132, 151, 171, 192, 214, 237, 261, 286, 313, 341, 370, 400, 431, 463, 496, 530, 566, 603, 641, 680, 720, 761, 803, 846, 890, 936, 983, 1031, 1080, 1130, 1181, 1233, 1286, 1340, 1395, 1451, 1509

Offset

1,1

Comments

Complement means that c(i) is the i-th member of the sorted list of integers >=1 that are not in the set {a(1),...,a(i-1)}. - R. J. Mathar, Aug 06 2015

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
a[1] = 3; c[1] = 1; c[2] = 2;
a[n_] := a[n] = a[n - 1] + c[n - 1];
c[n_] := c[n] = mex[Flatten[Table[{a[i], c[i]}, {i, 1, n - 1}]]];
Table[a[n], {n, 80}]  (* A022935 *)
Table[c[n], {n, 80}]
(* Clark Kimberling, May 15 2012 *)

Crossrefs

Sequence in context: A348529 A069825 A093040 * A374762 A192813 A048229

Adjacent sequences: A022932 A022933 A022934 * A022936 A022937 A022938

Keyword

nonn

Author

Clark Kimberling

Status

approved