0,3

A. Cayley, Calculation of the minimum N.G.F. of the binary seventhic, Collected Mathematical Papers. Vols. 1-13, Cambridge Univ. Press, London, 1889-1897, Vol. 10, p. 408-419.

H. Gupta et al., Tables of Partitions. Royal Society Mathematical Tables, Vol. 4, Cambridge Univ. Press, 1958, p. 2.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

T. D. Noe, Table of n, a(n) for n=0..1000

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 355

a(n)=1+(a(n-2)+a(n-3)+a(n-4))-(2*a(n-7)+2*a(n-8)+a(n-9))+(a(n-11)+2*a(n-12)+2*a(n-13))- (a(n-16)+a(n-17)+a(n-18))+(a(n-20)) - Norman J. Meluch (norm(AT)iss.gm.com), Mar 09 2000

with(combstruct):ZL7:=[S, {S=Set(Cycle(Z, card<7))}, unlabeled]: seq(count(ZL7, size=n), n=0..50); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 24 2007

(Maple) a := n -> (Matrix(21, (i, j)-> if (i=j-1) then 1 elif j=1 then [1, 1, 0, 0, -1, 0, -2, 0, 1, 1, 1, 1, 0, -2, 0, -1, 0, 0, 1, 1, -1][i] else 0 fi)^n)[1, 1]; seq (a(n), n=0..50); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Jul 31 2008]

B:=[S, {S = Set(Sequence(Z, 1 <= card), card <=6)}, unlabelled]: seq(combstruct[count](B, size=n), n=0..50); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 21 2009]

CoefficientList[ Series[ 1/((1 - x)*(1 - x^2)*(1 - x^3)*(1 - x^4)*(1 - x^5)*(1 - x^6)), {x, 0, 60} ], x ]

Essentially same as A026812.

a(n)=A008284(n+6, 6), n >= 0.

Sequence in context: A036608 A136185 A026812 this_sequence A008629 A070289 A035961

Adjacent sequences: A001399 A001400 A001401 this_sequence A001403 A001404 A001405

nonn,easy

N. J. A. Sloane (njas(AT)research.att.com).