0,2

Number of binary trees of size n and height n-1, computed from size n=3 onward; i.e. A014480(n) = A073345(n+3,n+2). (For sizes n=0 through 2 there are no such trees.)

Also determinant of the n X n matrix M(i,j)=binomial(2i+2j,i+j) - Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 27 2004

Subdiagonal in triangle displayed in A128196. - Peter Luschny (peter(AT)luschny.de), Feb 26 2007

a(n) = (2n+1)*2^n = 4a(n-1)-4a(n-2) = 4*A052951(n-1) = a(n-1)+A052951(n) = a(n-1)*(2+4/(2n-1)) = A054582(n, n) - Henry Bottomley (se16(AT)btinternet.com), May 16 2001

E.g.f.: x*cosh(sqrt(2)*x) = x + 6x^3/3! + 20x^5/5! + 56x^7/7! +... - Ralf Stephan, Mar 03 2005

a(n)=A118416(n+1,n+1)=A118413(n+1,n+1); A001511(a(n))=A003602(a(n)); A117303(a(n))=a(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Apr 27 2006

Row sums of triangle A132775 - Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 29 2007

Row sums of triangle A134233 - Gary W. Adamson (qntmpkt(AT)yahoo.com), Oct 14 2007

(1 + 2*x)/(1-2*x)^2 = 1 + 6*x + 20*x^2 + 56*x^3 + 144*x^4 + 352*x^5 + 832*x^6 + ...

CoefficientList[ Series[(1 + 2*x)/(1 - 2*x)^2, {x, 0, 28}], x]

Cf. A118417.

Cf. A128196.

Cf. A132775.

Cf. A134233.

Sequence in context: A028492 A059822 A109903 this_sequence A048778 A048611 A127982

Adjacent sequences: A014477 A014478 A014479 this_sequence A014481 A014482 A014483

nonn

njas