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Search: id:A100477
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| A100477 |
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a(n) = 3*a(n-1)+2*a(n-2)+a(n-3) if n>=3 else a(n)=n |
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+0
2
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| 0, 1, 2, 8, 29, 105, 381, 1382, 5013, 18184, 65960, 239261, 867887, 3148143, 11419464, 41422565, 150254766, 545028892, 1977018773, 7171368869, 26013173045, 94359275646, 342275541897, 1241558350028, 4503585409524
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Weighted sum of the three previous terms.
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FORMULA
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O.g.f.: x(1-x)/(1-3x-2x^2-x^3). a(n)=A108153(n)-A108153(n-1). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 22 2008]
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EXAMPLE
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a(3)= 3*a(2)+2*a(1)+a(0) = 3*2+2*1+0 = 8
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PROGRAM
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(PERL) #!/usr/local/bin/perl -w $d=0; $c=1; $b=2; print "$d, $c, $b, "; $a=0; for (; ; ){ $a=3*$b+2*$c+$d; $d=$c; $c=$b; $b=$a; print "$a, "; last if ($a >2**61); } __END__
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CROSSREFS
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Adjacent sequences: A100474 A100475 A100476 this_sequence A100478 A100479 A100480
Sequence in context: A061230 A013559 A107025 this_sequence A011367 A009419 A000162
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KEYWORD
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easy,nonn
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AUTHOR
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gamo (gamo(AT)telecable.es), Nov 22 2004
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