A370962 a(n) = number of "lonesum" 2 X 2 X n tensors.

1, 14, 104, 644, 3668, 19964, 105764, 550844, 2836868, 14498204, 73695524, 373141244, 1883894468, 9490820444, 47735267684, 239788294844, 1203351134468, 6034279718684, 30241150798244, 151483730475644, 758527460524868, 3797063240264924, 19002992063903204

Offset

0,2

Links

Table of n, a(n) for n=0..22.

Don Knuth, Parades and poly-Bernoulli bijections, Mar 31 2024. See (19.11).

Filip Stappers, Problems concerning parades and poly-Bernoulli numbers, 2024. See Problem 9.

Index entries for linear recurrences with constant coefficients, signature (14,-71,154,-120).

Formula

From Filip Stappers, Aug 27 2024: (Start)

a(n) = 8*5^n - 4*4^n - 4*3^n + 2^n.

G.f.: (1-21*z^2-28*z^3)/((1-5*z)*(1-4*z)*(1-3*z)*(1-2*z)). (End)

Crossrefs

Cf. A370963, A370964, A370965.

Sequence in context: A162301 A161862 A266561 * A222369 A131709 A139614

Adjacent sequences: A370959 A370960 A370961 * A370963 A370964 A370965

Keyword

nonn,easy

Author

N. J. A. Sloane, Apr 04 2024

Extensions

a(7) from Michael S. Branicky, Apr 05 2024

a(8) from Michael S. Branicky, Apr 06 2024

a(9) from Michael S. Branicky, Apr 08 2024

a(10) from Michael S. Branicky, Apr 27 2024

a(0) and more terms from Filip Stappers, Aug 27 2024

Status

approved