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A059409 a(n) = 4^n * (2^n - 1). 3
0, 4, 48, 448, 3840, 31744, 258048, 2080768, 16711680, 133955584, 1072693248, 8585740288, 68702699520, 549688705024, 4397778075648, 35183298347008, 281470681743360, 2251782633816064, 18014329790005248, 144114913197948928 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Jordan's totient functions are described more fully in A059379 and A059380; for example, J_1(n) is Euler's totient function and J_2(n) the Moebius transform of squares.

REFERENCES

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 199, #3.

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..100

Index entries for linear recurrences with constant coefficients, signature (12,-32).

FORMULA

Equals J_n(8) (see A059379).

J_n(8) = 8^n - A024023(n) - A000225(n) - A000012(n).

a(n) = 4*A016152(n).

G.f.: 4*x / ( (8*x-1)*(4*x-1) ). - R. J. Mathar, Nov 23 2018

EXAMPLE

(4,48,448,3840,...) = (8,64,512,4096,...) - (2,12,56,240,...) - (1,3,7,15,...) - (1,1,1,1,...)

MAPLE

seq(4^n * (2^n - 1), n=0..100); # Muniru A Asiru, Jan 29 2018

MATHEMATICA

Table[4^n*(2^n - 1), {n, 0, 30}] (* G. C. Greubel, Jan 29 2018 *)

LinearRecurrence[{12, -32}, {0, 4}, 20] (* Harvey P. Dale, Oct 14 2019 *)

PROG

(PARI) { for (n = 0, 100, write("b059409.txt", n, " ", 4^n*(2^n - 1)); ) } \\ Harry J. Smith, Jun 26 2009

(MAGMA) [4^n*(2^n - 1): n in [0..40]]; // Vincenzo Librandi, 26 2011

(GAP) List([0..100], n->4^n * (2^n - 1)); # Muniru A Asiru, Jan 29 2018

CROSSREFS

Cf. A059379, A059380, A016152.

Sequence in context: A269180 A228701 A111903 * A297816 A297987 A298842

Adjacent sequences:  A059406 A059407 A059408 * A059410 A059411 A059412

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Alford Arnold, Jan 30 2001

STATUS

approved

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Last modified December 1 16:44 EST 2021. Contains 349430 sequences. (Running on oeis4.)