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A059511 Main diagonal of the array A059217. 1
1, 3, 26, 471, 13953, 627421, 39873948, 3406344237, 376591685322, 52319828460127, 8922977163384085, 1832831375530080986, 446306812127457163805, 127130280682997045232005, 41881054710966221044222595, 15800074329058136531647698779 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..240

MATHEMATICA

t[0, 0] = 1; t[0, _?EvenQ] = 1; t[_?OddQ, 0] = 1; t[n_, k_] /; OddQ[n + k](*up*):= t[n, k] = t[n + 1, k - 1] + Sum[t[n, j], {j, 0, k - 1}];

t[n_, k_] /; EvenQ[n + k](*down*):= t[n, k] = t[n - 1, k + 1] + Sum[t[j, k], {j, 0, n - 1}]; Table[t[n, n], {n, 0, 50}] (* G. C. Greubel, Sep 10 2017 *)

CROSSREFS

Sequence in context: A274778 A049088 A089041 * A112676 A103112 A064941

Adjacent sequences:  A059508 A059509 A059510 * A059512 A059513 A059514

KEYWORD

easy,nonn

AUTHOR

Floor van Lamoen, Jan 21 2001

EXTENSIONS

Terms a(11) onward added by G. C. Greubel, Sep 10 2017

STATUS

approved

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Last modified August 8 04:32 EDT 2020. Contains 336290 sequences. (Running on oeis4.)