0,2

With a different offset, number of n-permutations of 8 objects:r,s,t,u,v,z,x,y with repetition allowed, containing exactly five (5) u's. Example: a(1)=42 because we have

uuuuur, uuuuru, uuuruu, uuruuu, uruuuu, ruuuuu

uuuuus, uuuusu, uuusuu, uusuuu, usuuuu, suuuuu,

uuuuut, uuuutu, uuutuu, uutuuu, utuuuu, tuuuuu,

uuuuuv, uuuuvu, uuuvuu, uuvuuu, uvuuuu, vuuuuu,

uuuuuz, uuuuzu, uuuzuu, uuzuuu, uzuuuu, zuuuuu,

uuuuux, uuuuxu, uuuxuu, uuxuuu, uxuuuu, xuuuuu,

uuuuuy, uuuuyu, uuuyuu, uuyuuu, uyuuuu, yuuuuu.

G.f.:1/(1-7*x)^6. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 06 2008]

Expansion of 1/(1-7*x)^6. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 02 2008

seq(binomial(n+5, 5)*7^n, n=0..17);

Sequence in context: A020932 A036400 A050988 this_sequence A075511 A016094 A004361

Adjacent sequences: A140401 A140402 A140403 this_sequence A140405 A140406 A140407

A000389, A036084, A036219, A045543, A050982, A054849 [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 06 2008]

Cf. A000389, A036084, A036219, A045543, A050982, A054849.

nonn,new

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