A022443 Sequence and first differences include all positive integers except 2.

1, 4, 9, 15, 22, 30, 40, 51, 63, 76, 90, 106, 123, 141, 160, 180, 201, 224, 248, 273, 299, 326, 354, 383, 414, 446, 479, 513, 548, 584, 621, 659, 698, 739, 781, 824, 868, 913, 959, 1006, 1054, 1103, 1153, 1205, 1258, 1312, 1367, 1423, 1480, 1538, 1597, 1657, 1718

Offset

1,2

Comments

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

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

G. S. Kazandzidis, A General Formula for Some Number-Sequences, Math. Annalen, 147 (1962), 367-372.

Mathematica

Fold[Append[#1, #1[[-1]] + Complement[Range[Max@#1 + 3], #1][[#2]]] &, {1, 4}, Range[3, 50]] (* Ivan Neretin, Apr 05 2016 *)

Crossrefs

Cf. A005228 and references therein.

Sequence in context: A134227 A022945 A022948 * A281026 A079423 A285283

Adjacent sequences: A022440 A022441 A022442 * A022444 A022445 A022446

Keyword

nonn

Author

N. J. A. Sloane

Status

approved