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 A139641 a(n) = binomial(n+4, 4)*7^n. 5
 1, 35, 735, 12005, 168070, 2117682, 24706290, 271769190, 2853576495, 28852829005, 282757724249, 2699051004195, 25191142705820, 230595844768660, 2075362602917940, 18401548412539068, 161013548609716845 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS With a different offset, number of n-permutations (n=5) of 8 objects s, t, u, v, w, z, x, y with repetition allowed, containing exactly four (4)u's. Example: a(1)=35 because we have uuuus, uuusu, uusuu, usuuu, suuuu, uuuut, uuutu, uutuu, utuuu, tuuuu, uuuuv, uuuvu, uuvuu, uvuuu, vuuuu, uuuuw, uuuwu, uuwuu, uwuuu, wuuuu, uuuuz, uuuzu, uuzuu, uzuuu, zuuuu, uuuux, uuuxu, uuxuu, uxuuu, xuuuu, uuuuy, uuuyu, uuyuu, uyuuu, yuuuu. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..400 MAPLE seq(binomial(n+4, 4)*7^n, n=0..20); PROG (Sage)[lucas_number2(n, 7, 0)*binomial(n, 4)/7^4for n in xrange(4, 21)] # Zerinvary Lajos, Mar 13 2009 (MAGMA) [7^n* Binomial(n+4, 4): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011 CROSSREFS Sequence in context: A140405 A278361 A145603 * A240928 A028220 A028213 Adjacent sequences:  A139638 A139639 A139640 * A139642 A139643 A139644 KEYWORD nonn,easy AUTHOR Zerinvary Lajos, Jun 12 2008 STATUS approved

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Last modified July 15 20:24 EDT 2019. Contains 325056 sequences. (Running on oeis4.)