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A183292
Complement of A055999.
0
1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 86, 87, 88, 89, 90
OFFSET
1,2
FORMULA
(See the Mathematica code.)
MATHEMATICA
a=1/2; b=7/2;
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
(PARI) a(n)=n-1+ceil(sqrt(8*n+25)/2-5/2) \\ Charles R Greathouse IV, Jan 20 2016
CROSSREFS
Cf. A055999.
Sequence in context: A028968 A029598 A184004 * A039193 A028798 A138309
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 03 2011
STATUS
approved