A159747 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 10. See A159741 for details.

89, 504, 1490, 3525, 7617, 15808, 32192, 64960, 130496, 261568, 523712, 1048000, 2096576, 4193728, 8388032, 16776640, 33553856, 67108288, 134217152, 268434880, 536870336, 1073741248, 2147483072, 4294966720, 8589934016, 17179868608, 34359737792, 68719476160, 137438952896

Offset: 1

Author

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

Keywords

• nonn
• easy

Formula

Interpolate a(n)=(-2*n^4+22*n^3-107.5*n^2+276.5*n+1245)/3 offset 0 & b(n)=(2*n^4-18*n^3+77.5*n^2-184.5*n+1713)/3 offset 0. Add a leading 89. Binomially transform. [From Al Hakanson (hawkuu(AT)gmail.com), Jun 08 2009]

a(n) = T(n+9,n+1) with T defined in A159741. a(n) = 2^(n+8)-576 for n>=6. - R. J. Mathar, Feb 04 2021

Extensions

a(8) and beyond by R. J. Mathar, Feb 04 2021