0,2

With a different offset, number of n-permutations (n>=6) of 6 objects: t, u, v, z, x, y with repetition allowed, containing exactly six (6) u's.

If n=6 then a(0)= 1

Example: a(1)=35 because we have

uuuuuut, uuuuutu, uuuutuu, uuutuuu, uutuuuu, utuuuuu, tuuuuuu,

uuuuuuv, uuuuuvu, uuuuvuu, uuuvuuu, uuvuuuu, uvuuuuu, vuuuuuu,

uuuuuuz, uuuuuzu, uuuuzuu, uuuzuuu, uuzuuuu, uzuuuuu, zuuuuuu,

uuuuuux, uuuuuxu, uuuuxuu, uuuxuuu, uuxuuuu, uxuuuuu, xuuuuuu,

uuuuuuy, uuuuuyu, uuuuyuu, uuuyuuu, uuyuuuu, uyuuuuu, yuuuuuu.

G.f.:1/(1-5*x)^7. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 06 2008]

Expansion of 1/(1-5*x)^7. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 02 2008

seq(binomial(n+6, 6)*5^n, n=0..18);

Sequence in context: A126925 A010987 A112504 this_sequence A139641 A028220 A028213

Adjacent sequences: A140402 A140403 A140404 this_sequence A140406 A140407 A140408

Cf. A000579, A002409, A036220, A036226, A050988, A054337, A140406.

nonn,new

Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 16 2008