A159746 If an array is made of columns of -nacci sequences, fibo-, tribo- etc. all starting w. 1,1,2 etc, the NW to SE diagonals can be extended by computation. The above is diagonal 9. See A159741 for details.

55, 274, 773, 1793, 3840, 7936, 16128, 32512, 65280, 130816, 261888, 524032, 1048320, 2096896, 4194048, 8388352, 16776960, 33554176, 67108608, 134217472, 268435200, 536870656, 1073741568, 2147483392, 4294967040, 8589934336, 17179868928, 34359738112

Offset: 1

Author

Al Hakanson (hawkuu(AT)gmail.com), Apr 20 2009

Keywords

• nonn
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-2).

Programs

Mathematica

LinearRecurrence[{3,-2},{55,274,773,1793,3840,7936},30] (* Harvey P. Dale, Aug 18 2022 *)

Formula

Interpolate a(n)=(4*n^3-30*n^2+92*n+657)/3 offset 0 & b(n)=(-4*n^3+24*n^2-65*n+840)/3 offset 0. Add 55 as a leader. Binomially transform. [From Al Hakanson (hawkuu(AT)gmail.com), Jun 08 2009]

a(n) = 2^(7+n)-256 for n>=5. - R. J. Mathar, Feb 04 2021

Extensions

a(7) and beyond by R. J. Mathar, Feb 04 2021