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A159742 If an array is made of columns of -nacci sequences (Fibonacci, tribonacci, etc.), all starting with 1,1,2,..., the NW-to-SE diagonals can be extended by computation. This sequence is diagonal 6. See A159741 for details. 2
13, 44, 108, 236, 492, 1004, 2028, 4076, 8172, 16364, 32748, 65516, 131052, 262124, 524268, 1048556, 2097132, 4194284, 8388588, 16777196, 33554412, 67108844, 134217708, 268435436, 536870892, 1073741804, 2147483628, 4294967276, 8589934572, 17179869164 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (3,-2).

FORMULA

From R. J. Mathar, Apr 22 2009: (Start)

a(n) = 3*a(n-1) - 2*a(n-2), n>3.

a(n) = 16*2^n - 20, n>1. (End)

MAPLE

T := proc(n, m) option remember ; if n < 0 then 0; elif n <= 1 then 1; elif n = 2 then 2; else add(procname(n-i, m), i=1..m) ; fi: end: A159742 := proc(n) T(n+5, n+1) ; end: seq(A159742(n), n=1..40) ; # R. J. Mathar, Apr 22 2009

MATHEMATICA

CoefficientList[Series[(2*z^2 + 5*z + 13)/(2*z^2 - 3*z + 1), {z, 0, 100}], z] (* Vladimir Joseph Stephan Orlovsky, Jul 08 2011 *)

Join[{13}, Table[4*(2^(n + 2) - 5), {n, 2, 50}]] (* G. C. Greubel, May 22 2018 *)

LinearRecurrence[{3, -2}, {13, 44, 108}, 30] (* Harvey P. Dale, Jul 10 2018 *)

PROG

(PARI) for(n=1, 30, print1(if(n==1, 13, 4*(2^(n+2) - 5)), ", ")) \\ G. C. Greubel, May 22 2018

(MAGMA) [13] cat [4*(2^(n+2) - 5): n in [2..30]]; // G. C. Greubel, May 22 2018

CROSSREFS

Sequence in context: A033652 A026914 A226514 * A098385 A048364 A254675

Adjacent sequences:  A159739 A159740 A159741 * A159743 A159744 A159745

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

More terms from R. J. Mathar, Apr 22 2009

STATUS

approved

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Last modified June 21 14:17 EDT 2021. Contains 345364 sequences. (Running on oeis4.)