A147818 - OEIS

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A147818

Period 4: repeat [5, 9, 9, 5].

5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5, 9, 9, 5, 5

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OFFSET

1,1

COMMENTS

Last digit of the number whose binary representation is the concatenation of n 1's, 2n-1 0's and n 1's.

a(n) is the final digit of A147539(n).

LINKS

Table of n, a(n) for n=1..105.

Index entries for linear recurrences with constant coefficients, signature (1,-1,1).

FORMULA

a(n+1) = 7-2*cos(Pi*n/2)+2*sin(Pi*n/2). - R. J. Mathar, Oct 08 2011

a(n) = a(n-1)-a(n-2)+a(n-3) for n>3. G.f.: x*(5*x^2+4*x+5)/((1-x)*(x^2+1)). [Colin Barker, Nov 04 2012]

a(n) = a(n-4) for n>4. - Wesley Ivan Hurt, Jul 09 2016

MAPLE

A010879 := proc(n) n mod 10; end:

A147539 := proc(n) 2^n-1+2^(4*n-1)-2^(3*n-1); end:

A147818 := proc(n) A010879(A147539(n)); end: # R. J. Mathar, Jan 22 2009

seq(op([5, 9, 9, 5]), n=1..40); # Wesley Ivan Hurt, Jul 09 2016

MATHEMATICA

PadRight[{}, 100, {5, 9, 9, 5}] (* Wesley Ivan Hurt, Jul 09 2016 *)

PROG

(Magma) &cat [[5, 9, 9, 5]^^30]; // Wesley Ivan Hurt, Jul 09 2016

CROSSREFS

Cf. A138120, A147539.

Sequence in context: A085566 A076390 A321632 * A345739 A055199 A147777

Adjacent sequences: A147815 A147816 A147817 * A147819 A147820 A147821

KEYWORD

base,easy,nonn

AUTHOR

Omar E. Pol, Nov 14 2008, Jan 25 2009

EXTENSIONS

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

STATUS

approved