7,2

With a different offset, number of n-permutations of 8 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly seven u's. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 01 2008

With a different offset, number of n-permutations of 8 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly seven (7) u's. Example: a(1)=56 because we have uuuuuuur, uuuuuuru, uuuuuruu, uuuuruuu, uuuruuuu, uuruuuuu, uruuuuuu, ruuuuuuu, uuuuuuus, uuuuuusu, uuuuusuu, uuuusuuu, uuusuuuu, uusuuuuu, usuuuuuu, suuuuuuu, uuuuuuut, uuuuuutu, uuuuutuu, uuuutuuu, uuutuuuu, uutuuuuu, utuuuuuu, tuuuuuuu, uuuuuuuv, uuuuuuvu, uuuuuvuu, uuuuvuuu, uuuvuuuu, uuvuuuuu, uvuuuuuu, vuuuuuuu, uuuuuuuz, uuuuuuzu, uuuuuzuu, uuuuzuuu, uuuzuuuu, uuzuuuuu, uzuuuuuu, zuuuuuuu, uuuuuuux, uuuuuuxu, uuuuuxuu, uuuuxuuu, uuuxuuuu, uuxuuuuu, uxuuuuuu, xuuuuuuu, uuuuuuuy, uuuuuuyu, uuuuuyuu, uuuuyuuu, uuuyuuuu, uuyuuuuu. uyuuuuuu, yuuuuuuu. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 09 2008]

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

G.f.:=1/(1-7*x)^8 a(n)=C(n+7, 7)*7^n, n>=0. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 09 2008]

seq(binomial(n+7, 7)*7^n, n=0..17); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 01 2008

seq(binomial(n+7, 7)*7^n, n=0..17); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 09 2008]

(Other) SAGE:[lucas_number2(n, 7, 0)*binomial(n, 7)/7^7 for n in xrange(7, 23)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 13 2009]

Cf. A000027, A001788, A036216, A040075, A050982, A050988.

Cf. A000027, A001788, A036216, A040075, A050982, A050988, A059297, A059300, .

Sequence in context: A035723 A035799 A017719 this_sequence A140406 A075512 A000504

Adjacent sequences: A050986 A050987 A050988 this_sequence A050990 A050991 A050992

nonn

Eric Weisstein (eric(AT)weisstein.com)