A022953 a(n) = a(n-1) + c(n+1) for n >= 3, a( ) increasing, given a(1)=1, a(2)=7; where c( ) is complement of a( ).

1, 7, 12, 18, 26, 35, 45, 56, 69, 83, 98, 114, 131, 150, 170, 191, 213, 236, 260, 285, 312, 340, 369, 399, 430, 462, 495, 529, 565, 602, 640, 679, 719, 760, 802, 845, 889, 935, 982, 1030, 1079, 1129, 1180, 1232, 1285, 1339, 1394, 1451, 1509, 1568

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

Here "complement" refers to the numbers not in the sequence.

Links

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

Crossrefs

Essentially same as A005228.

Programs

Mathematica

Fold[Append[#1, #1[[-1]] + Complement[Range[Max@#1 + 3], #1][[#2 + 1]]] &, {1, 7}, Range[3, 50]] (* Ivan Neretin, Apr 05 2016 *)