A118027 a(0) = 0, a(n) = a(n-1) + (smallest integer which is >= n and is missing from the earlier terms of the sequence).

0, 1, 3, 7, 11, 16, 22, 30, 38, 47, 57, 69, 81, 94, 108, 123, 140, 157, 175, 194, 214, 235, 258, 281, 305, 330, 356, 383, 411, 440, 471, 502, 534, 567, 601, 636, 672, 709, 748, 787, 827, 868, 910, 953, 997, 1042, 1088, 1136, 1184, 1233, 1283, 1334, 1386, 1439

Offset: 0

Author

Leroy Quet, Apr 10 2006

Keywords

• easy
• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A118026, A118028, A118029, A118030, A094589.

Programs

Mathematica

a = {1}; Do[k = i; While[MemberQ[a, k], k++]; AppendTo[a, a[[i - 1]] + k], {i, 2, 53}]; {0}~Join~a (* Michael De Vlieger, Sep 16 2017 *)

Extensions

More terms from Wendy Kalasky (wkk107(AT)psu.edu), Apr 26 2006