A166769 Number of n X 5 1..2 arrays containing at least one of each value, and all equal values connected.

8, 90, 712, 4942, 32426, 206392, 1284728, 7855758, 47333834, 281703020, 1659086104, 9684388606, 56098465446, 322820680276, 1847076802248, 10515831592642, 59608838934806, 336604310563828, 1894399026364292, 10630153480987994, 59494181482941446, 332206086480550664

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..500

Index entries for linear recurrences with constant coefficients, signature (24,-245,1403,-5022,11858, -18861,19829,-12118,1011,5487, -4942,1470,543,-565,78,67,-12,-4).

Formula

G.f.: 2*x*(4 - 51*x + 256*x^2 - 660*x^3 + 1082*x^4 - 1431*x^5 + 698*x^6 + 4667*x^7 - 15736*x^8 + 23396*x^9 - 16421*x^10 + 1174*x^11 + 4664*x^12 - 1000*x^13 - 500*x^14 + 100*x^15 - 221*x^16 - 99*x^17 - 10*x^18)/((1 - x)^2*(1 - 7*x + 12*x^2 - 7*x^3 + 3*x^4 + 2*x^5)^2*(1 - 8*x + 15*x^2 - 5*x^3 - 9*x^4 + 2*x^5 + x^6)). - Andrew Howroyd, Dec 12 2024

Example

Some solutions for n=4
...1.1.1.2.2...1.1.1.2.2...1.1.1.1.1...2.2.2.2.1...1.1.1.2.2...1.1.1.2.2
...1.1.1.1.2...1.2.2.2.1...1.2.1.1.1...2.2.1.1.1...1.2.1.1.2...1.1.1.1.2
...1.2.2.2.2...1.1.1.2.1...1.2.1.2.1...2.1.1.1.1...1.2.1.1.2...1.1.1.1.2
...1.1.1.1.2...1.1.1.1.1...1.2.2.2.2...2.2.2.2.2...1.2.2.2.2...1.1.1.1.1
------
...1.1.1.1.2...2.2.2.2.2...1.1.1.1.1...1.1.2.2.2...1.1.1.2.2...1.1.1.1.1
...2.2.2.1.2...1.1.1.1.2...2.2.2.2.1...1.2.2.2.2...1.1.1.1.2...1.2.1.1.1
...2.2.2.2.2...2.2.2.2.2...1.1.1.2.1...1.2.2.1.1...1.1.1.2.2...2.2.1.1.2
...2.2.2.2.2...2.2.2.2.2...1.1.1.1.1...1.1.1.1.1...1.1.1.2.2...2.2.2.2.2

Crossrefs

Twice row 5 of A378932.

Sequence in context: A128304 A247728 A056784 * A323960 A187667 A331512

Adjacent sequences: A166766 A166767 A166768 * A166770 A166771 A166772

Keyword

nonn

Author

R. H. Hardin, Oct 21 2009

Extensions

a(10) onwards from Andrew Howroyd, Dec 12 2024

Status

approved