A186348 Adjusted joint rank sequence of (f(i)) and (g(j)) with f(i) after g(j) when f(i)=g(j), where f(i)=8i and g(j)=j^2. Complement of A186349.

3, 6, 7, 9, 11, 12, 14, 16, 17, 18, 20, 21, 23, 24, 25, 27, 28, 30, 31, 32, 33, 35, 36, 37, 39, 40, 41, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 59, 60, 61, 62, 63, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 77, 78, 79, 80, 81, 83, 84, 85, 86, 87, 88

Offset

1,1

Links

Table of n, a(n) for n=1..66.

Formula

a(n) = n+floor(sqrt(8n)).

Example

First, write
....8....16..24..32..40..48..56..64..72..80.. (8i)
1..4..9..16...25...36......49....64.......81 (squares)
Then replace each number by its rank, where ties are settled by ranking 8i after the square:
p=(3,6,7,9,11,12,14,16,17,..)=A186348=a(n).
q=(1,2,4,5,8,10,13,15,19,...)=A186349=n+floor((n^2-1)/8).

Mathematica

(* adjusted joint rank sequences p and q, using general formula for ranking 1st degree u*n+v and 2nd degree x*n^2+y*n+z *)
d=-1/2; u=8; v=0; x=1; y=0;
h[n_]:=(-y+(4x(u*n+v-d)+y^2)^(1/2))/(2x);
a[n_]:=n+Floor[h[n]];
Table[a[n], {n, 1, 120}]  (* A186348 *)

Prog

(PARI) a(n)=n+sqrtint(8*n) \\ Charles R Greathouse IV, Jul 05 2013

Crossrefs

Cf. A186346, A186347, A186349.

Sequence in context: A176237 A187811 A324696 * A071822 A268380 A268378

Adjacent sequences: A186345 A186346 A186347 * A186349 A186350 A186351

Keyword

nonn,easy

Author

Clark Kimberling, Feb 20 2011

Status

approved