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A053643 a(n) = ceiling(C(n,6)/n). 2
0, 0, 0, 0, 0, 1, 1, 4, 10, 21, 42, 77, 132, 215, 334, 501, 728, 1032, 1428, 1938, 2584, 3392, 4389, 5609, 7084, 8855, 10964, 13455, 16380, 19793, 23751, 28319, 33563, 39556, 46376, 54106, 62832, 72650, 83657, 95960, 109668, 124900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,8

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

R. L. Graham and N. J. A. Sloane, Lower bounds for constant weight codes, IEEE Trans. Inform. Theory, 26 (1980), 37-43.

FORMULA

From Robert Israel, Nov 01 2015: (Start)

a(n) = ceiling(A000389(n-1)/6).

G.f.: (x^52 -2*x^51 +4*x^50 -4*x^49 +2*x^48 +x^47 -x^46 +2*x^44 -2*x^43 +x^42 -x^41 +4*x^40 -5*x^39 +4*x^38 -2*x^37 +3*x^36 -5*x^35 +5*x^34 -2*x^33 -2*x^32 +5*x^31 -5*x^30 +2*x^29 +2*x^28 -5*x^27 +5*x^26 -2*x^25 -2*x^24 +5*x^23 -5*x^22 +2*x^21 +2*x^20 -5*x^19 +5*x^18 -3*x^17 +4*x^16 -7*x^15 +9*x^14 -7*x^13 +5*x^12 -4*x^11 +4*x^10 -2*x^9 +3*x^7 -4*x^6 +x^5 +6*x^4 -10*x^3 +9*x^2 -4*x +1)*x^6/((x -1)^6*(x +1)*(x^4 +1)*(x^2 +x +1)*(x^2 -x +1)*(x^6 +x^3 +1)*(x^6 -x^3 +1)*(x^8 -x^4 +1)*(x^24 -x^12 +1)).

(End)

MAPLE

seq(ceil(binomial(n, 5)/6), n=0..41); # Zerinvary Lajos, Jan 12 2009

MATHEMATICA

Table[Ceiling[Binomial[n, 6]/n], {n, 42}] (* Michael De Vlieger, Nov 01 2015 *)

PROG

(PARI) vector(100, n, ceil(binomial(n, 6)/n)) \\ Altug Alkan, Nov 01 2015

(MAGMA) [Ceiling(Binomial(n, 6)/n) : n in [1..50]]; // Wesley Ivan Hurt, Nov 01 2015

CROSSREFS

Cf. A000389, A000579, A053618.

Sequence in context: A121497 A132925 A264079 * A111927 A290998 A227803

Adjacent sequences:  A053640 A053641 A053642 * A053644 A053645 A053646

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Mar 25 2000

STATUS

approved

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Last modified April 20 22:22 EDT 2019. Contains 322310 sequences. (Running on oeis4.)