A094077 a(1)=1 and, for n>1, a(n)=a(n-1)+n if n is even and a(n)=smallest positive integer which has not yet appeared in the sequence if n is odd.

1, 3, 2, 6, 4, 10, 5, 13, 7, 17, 8, 20, 9, 23, 11, 27, 12, 30, 14, 34, 15, 37, 16, 40, 18, 44, 19, 47, 21, 51, 22, 54, 24, 58, 25, 61, 26, 64, 28, 68, 29, 71, 31, 75, 32, 78, 33, 81, 35, 85, 36, 88, 38, 92, 39, 95, 41, 99, 42, 102, 43, 105, 45, 109, 46, 112, 48, 116, 49, 119

Offset: 1

Author

John W. Layman, Apr 29 2004

Keywords

• nonn

Comments

A001951 and A001952 are the bisections of this sequence. - Klaus Brockhaus and Henry Bottomley, Feb 04 2006. This implies the asymptotic result stated in the formula line.

Formula

For even n, the ratio a(n)/a(n-1) is asymptotic to 1+sqrt(2) as n becomes large.