A128022 a(1)=1, a(n) = the multiple of n which is >= (sum{k=1 to n-1} a(k)) and is < (n + sum{k=1 to n-1} a(k)).

1, 2, 3, 8, 15, 30, 63, 128, 252, 510, 1012, 2028, 4056, 8120, 16230, 32464, 64923, 129852, 259711, 519420, 1038828, 2077658, 4155318, 8310648, 16621300, 33242586, 66485178, 132970348, 265940701, 531881400, 1063762799, 2127525600

Offset: 1

Author

Leroy Quet, Feb 11 2007

Keywords

• easy
• nonn

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..3322

Crossrefs

Cf. A128020, A128023.

Programs

Mathematica

f[l_List] := Block[{n = Length[l] + 1}, Append[l, n*(Ceiling[Plus @@ l/n])]]; Nest[f, {1}, 33] (* Ray Chandler, Feb 12 2007 *)
Fold[Append[#1, #2 Ceiling@ Total[#1/#2]] &, {1}, Range[2, 32]] (* Michael De Vlieger, Oct 11 2017 *)

Formula

a(1)=1, a(n) = n * ceiling(sum{k=1 to n-1} a(k) /n).

Extensions

Extended by Ray Chandler, Feb 12 2007