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A048476 a(n) = T(4,n), array T given by A048472. 1
1, 6, 21, 61, 161, 401, 961, 2241, 5121, 11521, 25601, 56321, 122881, 266241, 573441, 1228801, 2621441, 5570561, 11796481, 24903681, 52428801, 110100481, 230686721, 482344961, 1006632961, 2097152001, 4362076161, 9059696641, 18790481921, 38923141121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

n-th difference of a(n), a(n-1), ..., a(0) is (5, 10, 15, ...).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (5,-8,4).

FORMULA

a(n) = 5*n * 2^(n-1) + 1.

a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3) for n>2. G.f.: (1+x-x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Feb 18 2016

PROG

(MAGMA) [5*n * 2^(n-1) + 1: n in [0..30]]; // Vincenzo Librandi, Sep 23 2011

(PARI) Vec((1+x-x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 18 2016

CROSSREFS

Sequence in context: A012593 A276235 A334833 * A122678 A256569 A132130

Adjacent sequences:  A048473 A048474 A048475 * A048477 A048478 A048479

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified September 19 06:16 EDT 2020. Contains 337177 sequences. (Running on oeis4.)