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A118231 Triangle, read by rows, equal to the matrix square of triangle A118229. +0
3
1, -2, 1, -2, 0, 1, 4, -2, -2, 1, -2, 0, 0, 0, 1, 2, 1, 1, -2, -2, 1, 4, 0, -2, 0, -2, 0, 1, -6, 1, 6, -2, 1, 0, -2, 1, -4, 0, 1, 0, 3, 0, -2, 0, 1, 6, -1, -6, 4, -1, -2, 4, -2, -2, 1, -4, 0, 3, 0, 1, 0, -2, 0, 0, 0, 1, 4, 0, -3, -1, -1, 1, 2, 1, 1, -2, -2, 1, 14, 0, -7, 0, -7, 0, 6, 0, -2, 0, -2, 0, 1, -14, 0, 3, 1, 10, 0, -4, -2, 3, 0, 1, 0, -2, 1 (list; table; graph; listen)
OFFSET

1,2

COMMENT

Describes the sequence transformation of triangle A118229 iterated twice. Also equals the matrix inverse of triangle A118233.

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

Triangle begins:

1;

-2, 1;

-2, 0, 1;

4,-2,-2, 1;

-2, 0, 0, 0, 1;

2, 1, 1,-2,-2, 1;

4, 0,-2, 0,-2, 0, 1;

-6, 1, 6,-2, 1, 0,-2, 1;

-4, 0, 1, 0, 3, 0,-2, 0, 1;

6,-1,-6, 4,-1,-2, 4,-2,-2, 1;

-4, 0, 3, 0, 1, 0,-2, 0, 0, 0, 1;

4, 0,-3,-1,-1, 1, 2, 1, 1,-2,-2, 1;

14, 0,-7, 0,-7, 0, 6, 0,-2, 0,-2, 0, 1; ...

PROGRAM

(PARI) T(n, k)=if(n<k|k<0, 0, (matrix(n, n, r, c, if(r>=c, if(gcd(r-c+1, c)==1, 1, 0)))^-2)[n, k])

CROSSREFS

Cf. A118229, A118233 (inverse).

Sequence in context: A156837 A129559 A129680 this_sequence A166453 A118233 A159955

Adjacent sequences: A118228 A118229 A118230 this_sequence A118232 A118233 A118234

KEYWORD

sign,tabl

AUTHOR

Leroy Quet, Paul D. Hanna (pauldhanna(AT)juno.com), Apr 16 2006

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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