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A100217 Diagonal sums of a binomial number triangle. 1
1, 1, 4, 12, 42, 149, 543, 2007, 7501, 28265, 107196, 408653, 1564506, 6010964, 23164467, 89501021, 346588092, 1344804060, 5227147969, 20349230347, 79330194097, 309653982738, 1210071825851, 4733665388134, 18535196846866 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

Diagonal sums of A100100.

FORMULA

a(n)=sum{k=0..floor(n/2), binomial(2n-3k-1, n-2k)}.

CROSSREFS

Sequence in context: A149344 A178078 A135489 * A149345 A149346 A149347

Adjacent sequences:  A100214 A100215 A100216 * A100218 A100219 A100220

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Nov 08 2004

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Last modified February 17 02:43 EST 2012. Contains 205978 sequences.