A026488 a(n) is the least positive integer > a(n-1) and not a(i)*a(j)-a(k) for 1 <= i <= j <= k <= n, where a(1) = 1.

1, 3, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 103, 106, 109, 112, 115, 118, 121, 124, 127, 130, 133, 136, 139, 142, 145, 148, 151, 154, 157, 160, 163, 166, 169, 172

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

Conjecture: This is the increasing sequence of numbers congruent to 1 mod 3, with 3 inserted.

Conjecture holds for n <= 1300. - Sean A. Irvine, Oct 12 2019

Crossrefs

Cf. A026477, A016777.

Extensions

Corrected and extended by Clark Kimberling, Oct 12 2019