A247731 Number of length 5+3 0..n arrays with no disjoint pairs in any consecutive four terms having the same sum

8, 656, 9392, 77236, 408644, 1668072, 5532212, 15837692, 40185476, 92896600, 198499032, 397892044, 754772008, 1366836516, 2376338664, 3988754296, 6488751232, 10269159692, 15853887820, 23940629936, 35432070592, 51496627304

Offset

1,1

Comments

Row 5 of A247726

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = -3*a(n-1) -6*a(n-2) -9*a(n-3) -10*a(n-4) -7*a(n-5) +2*a(n-6) +17*a(n-7) +36*a(n-8) +54*a(n-9) +64*a(n-10) +59*a(n-11) +35*a(n-12) -9*a(n-13) -67*a(n-14) -128*a(n-15) -177*a(n-16) -199*a(n-17) -182*a(n-18) -122*a(n-19) -24*a(n-20) +98*a(n-21) +222*a(n-22) +323*a(n-23) +378*a(n-24) +372*a(n-25) +299*a(n-26) +167*a(n-27) -5*a(n-28) -189*a(n-29) -354*a(n-30) -470*a(n-31) -516*a(n-32) -482*a(n-33) -372*a(n-34) -202*a(n-35) +202*a(n-37) +372*a(n-38) +482*a(n-39) +516*a(n-40) +470*a(n-41) +354*a(n-42) +189*a(n-43) +5*a(n-44) -167*a(n-45) -299*a(n-46) -372*a(n-47) -378*a(n-48) -323*a(n-49) -222*a(n-50) -98*a(n-51) +24*a(n-52) +122*a(n-53) +182*a(n-54) +199*a(n-55) +177*a(n-56) +128*a(n-57) +67*a(n-58) +9*a(n-59) -35*a(n-60) -59*a(n-61) -64*a(n-62) -54*a(n-63) -36*a(n-64) -17*a(n-65) -2*a(n-66) +7*a(n-67) +10*a(n-68) +9*a(n-69) +6*a(n-70) +3*a(n-71) +a(n-72)

Example

Some solutions for n=4
..3....1....1....4....3....1....1....1....4....2....1....4....1....0....4....0
..4....1....3....1....0....3....0....4....2....3....3....4....0....1....1....2
..4....3....4....1....4....0....4....4....4....0....3....2....1....0....3....0
..1....4....1....0....2....1....4....3....4....4....2....1....4....0....1....0
..0....3....4....4....1....0....4....0....1....4....1....4....4....4....1....4
..1....0....2....1....1....2....3....2....2....3....3....0....3....1....4....3
..1....3....0....2....3....4....2....2....4....4....1....2....4....1....3....4
..1....2....3....4....0....3....0....2....4....1....0....3....2....3....3....0

Crossrefs

Sequence in context: A267968 A253268 A235368 * A231849 A159621 A015106

Adjacent sequences: A247728 A247729 A247730 * A247732 A247733 A247734

Keyword

nonn

Author

R. H. Hardin, Sep 23 2014

Status

approved