A263679 Number of length n arrays of permutations of 0..n-1 with each element moved by -4 to 4 places and with no two consecutive decreases.
1, 2, 5, 17, 70, 277, 1009, 3487, 11708, 39905, 137984, 481005, 1680187, 5852468, 20335048, 70581031, 244962297, 850636578, 2955043270, 10266945188, 35669911963, 123914096828, 430440925456, 1495206245569, 5193902810084
Offset: 1
Keywords
Examples
Some solutions for n=7 ..3....1....1....3....0....3....3....2....2....4....3....0....0....1....4....2 ..0....3....0....0....3....0....0....1....1....0....0....1....1....2....5....0 ..2....0....3....4....4....2....6....5....3....6....1....6....3....0....0....4 ..1....2....6....1....1....1....2....0....0....1....5....4....6....6....3....6 ..6....6....4....2....5....5....5....6....6....2....2....5....2....3....1....1 ..4....4....5....6....6....6....1....3....4....3....4....2....5....5....2....5 ..5....5....2....5....2....4....4....4....5....5....6....3....4....4....6....3
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A263683.
Formula
Empirical: a(n) = a(n-1) +4*a(n-2) +5*a(n-3) +15*a(n-4) +32*a(n-5) +83*a(n-6) +177*a(n-7) +484*a(n-8) +31*a(n-9) -763*a(n-10) -877*a(n-11) -1255*a(n-12) -8*a(n-13) +689*a(n-14) -1926*a(n-15) -6341*a(n-16) +168*a(n-17) +4160*a(n-18) +5193*a(n-19) +14170*a(n-20) -90*a(n-21) -10484*a(n-22) +4691*a(n-23) +28799*a(n-24) -8336*a(n-25) -10253*a(n-26) +4897*a(n-27) -51433*a(n-28) -110*a(n-29) +39213*a(n-30) -19619*a(n-31) -38190*a(n-32) +25392*a(n-33) +3232*a(n-34) -6950*a(n-35) +33047*a(n-36) +5995*a(n-37) -24598*a(n-38) -929*a(n-39) +32120*a(n-40) -17156*a(n-41) -5644*a(n-42) +9174*a(n-43) -13742*a(n-44) -3448*a(n-45) +8503*a(n-46) +1927*a(n-47) -8426*a(n-48) +2497*a(n-49) +1593*a(n-50) -1252*a(n-51) +2298*a(n-52) +216*a(n-53) -1058*a(n-54) -131*a(n-55) +755*a(n-56) -128*a(n-57) -143*a(n-58) +32*a(n-59) -166*a(n-60) +13*a(n-61) +57*a(n-62) +4*a(n-63) -18*a(n-64) -2*a(n-65) +2*a(n-66) +4*a(n-68) -a(n-70)
Comments