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A225800 Triangle of rising diagonals of A011973 (with rows displayed as centered text). 0
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 2, 1, 1, 5, 4, 1, 1, 7, 6, 1, 1, 1, 9, 8, 6, 3, 1, 1, 11, 10, 15, 10, 1, 1, 13, 12, 28, 21, 1, 1, 1, 15, 14, 45, 36, 10, 4, 1, 1, 17, 16, 66, 55, 35, 20, 1, 1, 19, 18, 91, 78, 84, 56, 1, 1, 1, 21, 20, 120, 105, 165, 120, 15, 5, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,11

COMMENTS

Row sums are A227300

LINKS

Table of n, a(n) for n=1..76.

FORMULA

r(n) = binomial[2n-k-2-3floor(k/2),floor(k/2)); {k, 0,...,floor((2n-1)/3)}. - John Molokach, Jul 29 2013

EXAMPLE

Triangle begins:

1;

1, 1;

1, 1;

1, 1, 1;

1, 1, 3, 2;

1, 1, 5, 4;

1, 1, 7, 6, 1;

1, 1, 9, 8, 6, 3;

1, 1, 11, 10, 15, 10;

1, 1, 13, 12, 28, 21, 1;

MATHEMATICA

Table[Binomial[2 n - k - 2 - 3 Floor[k/2], Floor[k/2]], {n, 1, 25}, {k, 0, Floor[(2 n - 1)/3]}] (* John Molokach, Jul 29 2013 *)

CROSSREFS

Cf. A011973, A000045, A227300, A005314, A224838.

Sequence in context: A046225 A269233 A123396 * A176669 A058280 A113185

Adjacent sequences:  A225797 A225798 A225799 * A225801 A225802 A225803

KEYWORD

nonn,tabf

AUTHOR

John Molokach, Jul 27 2013

STATUS

approved

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Last modified October 20 16:34 EDT 2018. Contains 316391 sequences. (Running on oeis4.)