2,2

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures}, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

Hearne and Wagner, Minimal covers of finite sets, Discr. Math. 5 (1973), 247-251.

Math. Mag. vol. 68, n4, p 274 Oct '95.

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures}, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

G.f.: (1 - x - x^2 ) / ((1 - x )^3*(1 - 2x)^2).

a(n)=(n+1)2^n-(n+1)(n+2)/2 - Paul Barry (pbarry(AT)wit.ie), Jan 27 2003

a:=n->sum(n*binomial(n, k)/2, k=2..n): seq(a(n), n=2..23); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 08 2007

a:=n->sum(sum(binomial(n, j)/2, j=2..n), k=1..n): seq(a(n), n=2..23); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 08 2007

A003469:=(-1+z+z**2)/(2*z-1)**2/(z-1)**3; [Conjectured by S. Plouffe in his 1992 dissertation.]

Partial sums of A053221.

Cf. A053218.

Sequence in context: A001925 A002663 A099855 this_sequence A027992 A032195 A111566

Adjacent sequences: A003466 A003467 A003468 this_sequence A003470 A003471 A003472

nonn,easy

njas