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A131086 Triangle read by rows: T(n,k)=2*binom(n,k)-(-1)^(n-k) (0<=k<=n). +0
2
1, 3, 1, 1, 5, 1, 3, 5, 7, 1, 1, 9, 11, 9, 1, 3, 9, 21, 19, 11, 1, 1, 13, 29, 41, 29, 13, 1, 3, 13, 43, 69, 71, 41, 15, 1, 1, 17, 55, 113, 139, 113, 55, 17, 1, 3, 17, 73, 167, 253, 251, 169, 71, 19, 1, 1, 21, 89, 241, 419, 505, 419, 241, 89, 21, 1, 3, 21, 111, 329 (list; table; graph; listen)
OFFSET

0,2

COMMENT

Row sums = A051049 starting (1, 4, 7, 16, 31, 64,...).

FORMULA

G.f.=G(t,z)=(1+3z-tz-2tz^2)/[(1+z)(1-tz)(1-z-tz)]. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 21 2007

EXAMPLE

First few rows of the triangle are:

1;

3, 1;

1, 5, 1;

3, 5, 7, 1;

1, 9, 11, 9, 1;

3, 9, 21, 19, 11, 1;

1, 13, 29, 41, 29, 13, 1;

...

MAPLE

T := proc (n, k) if k <= n then 2*binomial(n, k)-(-1)^(n-k) else 0 end if end proc: for n from 0 to 11 do seq(T(n, k), k = 0 .. n) end do; # yields sequence in triangular form - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 21 2007

CROSSREFS

Cf. A000012, A051049.

Sequence in context: A046230 A046229 A124738 this_sequence A069002 A076334 A014475

Adjacent sequences: A131083 A131084 A131085 this_sequence A131087 A131088 A131089

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson (qntmpkt(AT)yahoo.com), Jun 14 2007

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 21 2007

Sequence corrected by njas, Sep 30 2007

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.


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