a(1)=1, a(2)=3, otherwise a(n) = least positive integer > a(n-1) and not a(i) + a(j) + a(k) for 1 <= i < j < k <= n.

A026475

a(1)=1, a(2)=3, otherwise a(n) = least positive integer > a(n-1) and not a(i) + a(j) + a(k) for 1 <= i < j < k <= n.

Terms

    a(0) =1a(1) =3a(2) =4a(3) =5a(4) =6a(5) =7a(6) =19a(7) =20a(8) =21a(9) =22a(10) =36a(11) =37a(12) =38a(13) =39a(14) =53a(15) =54a(16) =55a(17) =69a(18) =70a(19) =71a(20) =72a(21) =86a(22) =87a(23) =88a(24) =102a(25) =103a(26) =104a(27) =105a(28) =119a(29) =120

External references