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A173511 a(n) = 4*n^2 + floor(n/2). 7
0, 4, 17, 37, 66, 102, 147, 199, 260, 328, 405, 489, 582, 682, 791, 907, 1032, 1164, 1305, 1453, 1610, 1774, 1947, 2127, 2316, 2512, 2717, 2929, 3150, 3378, 3615, 3859, 4112, 4372, 4641, 4917, 5202, 5494, 5795, 6103, 6420, 6744, 7077, 7417, 7766, 8122 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = floor((2*n + 1/8)^2).
a(n+1) - a(n) = A173512(n).
a(n) = A002943(n) - A007494(n) = A007742(n) - A110654(n).
a(2*n) = A157474(n) for n>0.
a(n)= 2*a(n-1) -2*a(n-3) +a(n-4). G.f.: -x*(4+9*x+3*x^2)/((1+x)*(x-1)^3). - R. J. Mathar, Feb 21 2010
EXAMPLE
a(6) = 147; 4(6)^2 + floor(6/3) = 144 + 3 = 147.
MAPLE
A173511:=n->4*n^2 + floor(n/2); seq(A173511(k), k=0..100); # Wesley Ivan Hurt, Nov 01 2013
MATHEMATICA
Table[4n^2 + Floor[n/2], {n, 0, 100}] (* Wesley Ivan Hurt, Nov 01 2013 *)
LinearRecurrence[{2, 0, -2, 1}, {0, 4, 17, 37}, 50] (* Harvey P. Dale, Nov 23 2019 *)
PROG
(PARI) a(n) = 4*n^2 + n\2 \\ Charles R Greathouse IV, Jun 11 2015
(Python)
def A173511(n): return (n**2<<2)+(n>>1) # Chai Wah Wu, Jan 18 2023
CROSSREFS
Sequence in context: A120884 A267766 A273683 * A218925 A356347 A182868
KEYWORD
nonn,easy,changed
AUTHOR
Reinhard Zumkeller, Feb 20 2010
STATUS
approved

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Last modified March 28 14:13 EDT 2024. Contains 371254 sequences. (Running on oeis4.)