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A158920 Binomial trnasform of A008805 (triangular numbers with repeats). 0
1, 2, 6, 16, 41, 102, 248, 592, 1392, 3232, 7424, 16896, 38144, 85504, 190464, 421888, 929792, 2039808, 4456448, 9699328, 21037056, 45481984, 98041856, 210763776, 451936256, 966787072, 2063597568, 4395630592, 9344909312, 19830669312 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

FORMULA

A007318 * (1, 1, 3, 3, 6, 6, 10, 10, 15, 15,...) = binomial transform of triangular numbers A000217 with repeats.

G.f.: x(x-1)^4/(1-2x)^3. a(n)=6*a(n-1)-12*a(n-2)+8*a(n-3), n>5. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 02 2009]

EXAMPLE

a(4) = 16 = (1, 3, 3, 1) dot (1, 1, 3, 3) = (1 + 3 + 9 + 3).

MAPLE

A000217 := proc(n) n*(n+1)/2 ; end: A008805 := proc(n) A000217( 1+floor(n/2) ) ; end: L := [seq(A008805(n), n=0..100)] ; read("transforms"); BINOMIAL(L) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 02 2009]

CROSSREFS

Cf. A008805

Sequence in context: A018021 A074405 A068786 * A178438 A143123 A102699

Adjacent sequences:  A158917 A158918 A158919 * A158921 A158922 A158923

KEYWORD

nonn

AUTHOR

Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 30 2009

EXTENSIONS

Extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 02 2009

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Last modified February 15 07:42 EST 2012. Contains 205717 sequences.