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A112088 Number of leaf nodes in a binary tree. 77
2, 3, 5, 7, 11, 16, 24, 36, 54, 81, 122, 183, 274, 411, 617, 925, 1388, 2082, 3123, 4684, 7026, 10539, 15809, 23713, 35570, 53355, 80032, 120048, 180072, 270108, 405162, 607743, 911615, 1367422, 2051133, 3076700, 4615050, 6922575, 10383862 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

David W. Wilson, Table of n, a(n) for n=1..1000

Simon Strandgaard, About this sequence

FORMULA

a(1)=2; a(n)=floor((5+sum(a(1) to a(n-1)))/2) - Graeme McRae (g_m(AT)mcraefamily.com), Jun 09 2006

MATHEMATICA

f[n_] := Block[{a = 2, b = 0, c = 4}, Do[x = b + a; c -= x; If[c < 0, a *= 2; c += 2a]; b = Floor[(2a - c + 1)/2], {i, n}]; x]; Array[f, 40] (* Robert G. Wilson v (rgwv(at)rgwv.com), Jan 11 2006 *))

f[s_] := Append[s, Ceiling[2 + Plus @@ s/2]]; Nest[f, {2}, 38] (* Robert G. Wilson v (rgwv(at)rgwv.com), Jul 08 2006 *)

PROG

(Ruby) a, c=2, 4; p Array.new(99){c-=x=(a*4-c+1)/2; c+=2*a*=2 if c<0; x}

a:=2; b:=0; c:=4; p := proc() local x; global a, b, c; x := b + a; c := c - x; if(c<0) then a := a*2; c := c + a*2; end if; b := floor((a*2-c+1) / 2); x end proc: seq(p(), i=0..40);

CROSSREFS

Sequence in context: A023435 A091501 A083198 * A117792 A154888 A018057

Adjacent sequences:  A112085 A112086 A112087 * A112089 A112090 A112091

KEYWORD

easy,nonn

AUTHOR

Simon Strandgaard (neoneye(AT)gmail.com), Nov 29 2005

EXTENSIONS

More terms from Simon Strandgaard (neoneye(AT)gmail.com), Nov 29 2005

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Last modified February 12 12:15 EST 2012. Contains 205379 sequences.