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 A269431 Number of length-n 0..4 arrays with no repeated value greater than the previous repeated value. 1
 5, 25, 125, 615, 2995, 14455, 69235, 329430, 1558430, 7334806, 34364270, 160340610, 745362730, 3453222850, 15949215754, 73454841775, 337413819915, 1546145183895, 7068979186035, 32251365241137, 146853223312325, 667445619383425 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 20*a(n-1) - 155*a(n-2) + 560*a(n-3) - 810*a(n-4) - 136*a(n-5) + 810*a(n-6) + 560*a(n-7) + 155*a(n-8) + 20*a(n-9) + a(n-10). Empirical g.f.: x*(5 - 75*x + 400*x^2 - 810*x^3 + 120*x^4 + 810*x^5 + 560*x^6 + 155*x^7 + 20*x^8 + x^9) / (1 - 4*x - x^2)^5. - Colin Barker, Jan 21 2019 EXAMPLE Some solutions for n=7: ..3. .2. .3. .4. .2. .3. .1. .1. .1. .3. .0. .2. .0. .0. .0. .0 ..1. .1. .3. .1. .1. .2. .2. .3. .3. .2. .0. .2. .1. .1. .0. .3 ..4. .3. .4. .1. .0. .0. .2. .3. .1. .0. .2. .0. .4. .0. .0. .4 ..1. .2. .2. .0. .2. .2. .0. .4. .0. .0. .4. .4. .2. .2. .2. .4 ..1. .2. .1. .1. .2. .1. .4. .0. .2. .0. .0. .1. .4. .4. .1. .2 ..0. .4. .4. .1. .4. .0. .0. .3. .4. .1. .2. .2. .0. .3. .0. .4 ..4. .3. .3. .4. .3. .4. .2. .0. .2. .2. .1. .4. .4. .2. .4. .0 CROSSREFS Column 4 of A269435. Sequence in context: A126642 A269615 A269579 * A269686 A269490 A269772 Adjacent sequences: A269428 A269429 A269430 * A269432 A269433 A269434 KEYWORD nonn AUTHOR R. H. Hardin, Feb 26 2016 STATUS approved

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Last modified December 7 02:45 EST 2023. Contains 367622 sequences. (Running on oeis4.)