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Search: id:A036219
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| A036219 |
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Expansion of 1/(1-3*x)^6; 6-fold convolution of A000244 (powers of 3). |
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+0
2
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| 1, 18, 189, 1512, 10206, 61236, 336798, 1732104, 8444007, 39405366, 177324147, 773778096, 3288556908, 13660159464, 55616363532, 222465454128, 875957725629, 3400777052442, 13036312034361, 49400761393368
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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a(n)=A027465(n+6,6) (O. Gerard's triangle).
With a different offset, number of n-permutations of 4 objects: u,v,z,x with repetition allowed, containing exactly five (5) u's. Example: a(1)=18 because we have uuuuuv uuuuvu uuuvuu uuvuuu uvuuuu vuuuuu uuuuuz uuuuzu uuuzuu uuzuuu uzuuuu zuuuuu uuuuux uuuuxu uuuxuu uuxuuu uxuuuu xuuuuu. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 13 2008
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FORMULA
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a(n) = 3^n*binomial(n+5, 5); G.f. 1/(1-3*x)^6.
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MAPLE
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seq(binomial(n+5, 5)*3^n, n=0..19); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 13 2008
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CROSSREFS
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A000244, A027465.
Sequence in context: A036394 A023016 A073385 this_sequence A022646 A004314 A125406
Adjacent sequences: A036216 A036217 A036218 this_sequence A036220 A036221 A036222
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KEYWORD
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easy,nonn,new
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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