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Search: id:A147794
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| A147794 |
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Number of nodes at n-th level in tree in which top node is 1; each node k has children labeled 1, 2, ..., k*(k+1) at next level. |
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+0
3
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| 1, 2, 8, 120, 40456, 14354709112, 10145806838546891496456, 43814454551364119293851205505402899467594454136, 12230705010706858303154182089533811056819321112988144670126813673854225371091425\ 006635639297686024
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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See the reference in A058311 for a better way to compute this!
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MAPLE
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M:=4;
L[0]:=[1]; a[0]:=1;
for n from 1 to M do
L[n]:=[];
t1:=L[n-1];
tc:=nops(t1);
for i from 1 to tc do
t2:=t1[i];
for j from 1 to t2*(t2+1) do
L[n]:=[op(L[n]), j]; od:
a[n]:=nops(L[n]);
#lprint(n, L[n], a[n]);
od:
od:
[seq(a[n], n=0..M)];
p := proc(n, k) option remember; local j ; if n = 1 then k*(k+1); else sum( procname(n-1, j), j=1..k*(k+1)) ; fi; expand(%) ; end: A147794 := proc(n) if n = 0 then 1 ; else subs(k=1, p(n, k)) ; fi; end: for n from 0 do printf("%d, \n", A147794(n)) ; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 04 2009]
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CROSSREFS
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A variant of A058311. Cf. A147780.
Sequence in context: A064111 A112094 A009658 this_sequence A027530 A009360 A156497
Adjacent sequences: A147791 A147792 A147793 this_sequence A147795 A147796 A147797
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 03 2009
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 04 2009
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