A323121 Number of compositions of n where the difference between largest and smallest parts equals four.

0, 0, 2, 3, 12, 23, 61, 132, 294, 639, 1377, 2922, 6178, 12953, 27021, 56106, 116030, 239090, 491202, 1006361, 2056755, 4194230, 8536023, 17340787, 35168957, 71217347, 144012394, 290835635, 586637532, 1181960546, 2378920014, 4783326807, 9609050910, 19286596636

Offset: 4

Author

Alois P. Heinz, Jan 05 2019

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 4..3407

Crossrefs

Column k=4 of A214258.

Formula

a(n) ~ c * d^n, where d = 1.9659482366454853371899373759344013961513... is the real root of the equation d^5 - d^4 - d^3 - d^2 - d - 1 = 0 or d^6 - 2*d^5 + 1 = 0 and c = 0.53792611681915978492363258130015596032604545873525287924... is the real root of the equation 9584*c^5 - 9584*c^4 + 3160*c^3 - 480*c^2 + 35*c - 1 = 0. - Vaclav Kotesovec, Jan 07 2019