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A147794 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. 3
1, 2, 8, 120, 40456, 14354709112, 10145806838546891496456, 43814454551364119293851205505402899467594454136, 12230705010706858303154182089533811056819321112988144670126813673854225371091425006635639297686024 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

See the reference in A058311 for a better way to compute this!

LINKS

Table of n, a(n) for n=0..8.

MAPLE

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: # R. J. Mathar, May 04 2009

CROSSREFS

A variant of A058311. Cf. A147780.

Sequence in context: A064111 A112094 A009658 * A027530 A228064 A271846

Adjacent sequences:  A147791 A147792 A147793 * A147795 A147796 A147797

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, May 03 2009

EXTENSIONS

More terms from R. J. Mathar, May 04 2009

STATUS

approved

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Last modified September 22 12:19 EDT 2019. Contains 327307 sequences. (Running on oeis4.)