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A105522 Inverse of number triangle A105438. 3
1, -2, 1, 1, -2, 1, 2, 0, -2, 1, -2, 4, -1, -2, 1, -4, -1, 6, -2, -2, 1, 5, -10, 1, 8, -3, -2, 1, 10, 4, -18, 4, 10, -4, -2, 1, -14, 28, 0, -28, 8, 12, -5, -2, 1, -28, -14, 56, -8, -40, 13, 14, -6, -2, 1, 42, -84, -6, 96, -21, -54, 19, 16, -7, -2, 1, 84, 48, -180, 15, 150, -40, -70, 26, 18, -8, -2, 1, -132, 264, 33, -330, 55, 220, -66 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums A105523 have g.f. 1-xc(-x^2) where c(x) is the g.f. of A000108. Diagonal sums are A105524.

LINKS

Table of n, a(n) for n=0..84.

FORMULA

Riordan array ((1+2x+4x^2-(1+2x)sqrt(1+4x^2))/(2x^2), (sqrt(1+4x^2)-1)/(2x))

EXAMPLE

Rows begin {1}, {-2, 1}, {1, -2, 1}, {2, 0, -2, 1}, {-2, 4, -1, -2, 1}, ...

CROSSREFS

Sequence in context: A057856 A117939 A276167 * A131774 A078316 A207668

Adjacent sequences:  A105519 A105520 A105521 * A105523 A105524 A105525

KEYWORD

easy,sign,tabl

AUTHOR

Paul Barry, Apr 11 2005

STATUS

approved

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Last modified February 23 05:44 EST 2018. Contains 299473 sequences. (Running on oeis4.)