A074147 (2n-1) odd numbers followed by 2n even numbers.

1, 2, 4, 3, 5, 7, 6, 8, 10, 12, 9, 11, 13, 15, 17, 14, 16, 18, 20, 22, 24, 19, 21, 23, 25, 27, 29, 31, 26, 28, 30, 32, 34, 36, 38, 40, 33, 35, 37, 39, 41, 43, 45, 47, 49, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 62, 64, 66, 68, 70, 72

Offset: 1

Author

Amarnath Murthy, Aug 28 2002

Keywords

• nonn
• easy
• tabl

Examples

			As a triangular array:
1,
2, 4,
3, 5, 7,
6, 8, 10, 12,
9, 11, 13, 15, 17,
14, 16, 18, 20, 22, 24,
...
		

Links

• Ivan Neretin, Table of n, a(n) for n = 1..5050

Crossrefs

Cf. A074148, A074149 (row sums), A001614.

Programs

Maple

A074147 := proc(n,k)
    ceil((n-1)^2/2)+1+2*k ;
end proc:
seq(seq( A074147(n,k),k=0..n-1) ,n=1..12) ; # R. J. Mathar, Nov 02 2023

Mathematica

Flatten@Table[Ceiling[(n - 1)^2/2] + 2 k - 1, {n, 12}, {k, n}] (* Ivan Neretin, Dec 15 2016 *)

Formula

T(n,k) = A061925(n-1)+2k, 0<=kR. J. Mathar, Jul 17 2007, corrected Nov 02 2023

a(n) = A116941(n-1)+1. - Robert G. Wilson v, Mar 09 2017