A183298 Complement of A147875.

1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85

Offset

1,2

Links

Table of n, a(n) for n=1..80.

Formula

(See the Mathematica code.)

a(n) = n+floor(sqrt(2n/5)) if 2n > floor(sqrt(2n/5))(5*floor(sqrt(2n/5))+1) and a(n) = n+floor(sqrt(2n/5))-1 otherwise. - Chai Wah Wu, Oct 12 2024

Mathematica

a=5/2; b=3/2;
F[n_]:=a*n^2+b*n;
R[n_]:=(n/a+((b-1)/(2a))^2)^(1/2);
G[n_]:=n-1+Ceiling[R[n]-(b-1)/(2a)];
Table[F[n], {n, 60}]
Table[G[n], {n, 100}]

Prog

(Python)
from math import isqrt
def A183298(n): return n+(m:=isqrt((k:=n<<1)//5))-(k<=m*(5*m+1)) # Chai Wah Wu, Oct 12 2024

Crossrefs

Cf. A147875.

Sequence in context: A089590 A052406 A022306 * A081023 A165332 A031179

Adjacent sequences: A183295 A183296 A183297 * A183299 A183300 A183301

Keyword

nonn,changed

Author

Clark Kimberling, Jan 03 2011

Status

approved