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A023423
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Generalized Catalan Numbers.
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5
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1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 128, 257, 517, 1042, 2104, 4256, 8624, 17504, 35585, 72455, 147746, 301706, 616948, 1263240, 2589840, 5316033, 10924681, 22475831, 46290195
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,8
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LINKS
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Seiichi Manyama, Table of n, a(n) for n = 0..3028
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MAPLE
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A023423 := proc(n)
option remember;
if n <= 6 then
1;
else
procname(n-1)+add(procname(k)*procname(n-2-k), k=5..n-2) ;
end if;
end proc: # R. J. Mathar, Oct 10 2014
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MATHEMATICA
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a[0]=1; a[n_]:= a[n]=a[n-1] + Sum[a[k]*a[n-2-k], {k, 5, n-2}]; Table[a[n], {n, 0, 30}] (* modified by G. C. Greubel, Jan 01 2018 *)
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PROG
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(PARI) {a(n) = if(n==0, 1, a(n-1) + sum(k=5, n-2, a(k)*a(n-k-2)))};
for(n=0, 30, print1(a(n), ", ")) \\ G. C. Greubel, Jan 01 2018
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CROSSREFS
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Cf. A000108, A001006, A004148, A004149, A023421, A023422.
Sixth row of A064645.
Sequence in context: A275075 A275063 A186026 * A210544 A180210 A274861
Adjacent sequences: A023420 A023421 A023422 * A023424 A023425 A023426
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KEYWORD
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nonn,easy
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AUTHOR
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Olivier Gérard
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STATUS
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approved
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