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A037521
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Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,1,0.
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2
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2, 9, 36, 146, 585, 2340, 9362, 37449, 149796, 599186, 2396745, 9586980, 38347922, 153391689, 613566756, 2454267026, 9817068105, 39268272420, 157073089682, 628292358729, 2513169434916, 10052677739666, 40210710958665
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index to sequences with linear recurrences with constant coefficients, signature (4,0,1,-4).
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FORMULA
| a(n)=floor(4^(n+1)/7). [From Mircea Merca (mircea(AT)teacher.com), Dec 26 2010]
G.f. x*(2+x) ) / ( (1-x)*(1-4*x)*(1+x+x^2) ).
a(n) = +4*a(n-1)+a(n-3)-4*a(n-4).
a(n) = 4^(n+1)/7 -1/3 -(-1)^(n mod 3)*A167380(4 +(n mod 3))/21 = 2*A033140(n)+A033140(n-1) . - R. J. Mathar, Jan 08 2011
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MAPLE
| seq(floor(4^(n+1)/7), n=1..30); [From Mircea Merca (mircea(AT)teacher.com), Dec 26 2010]
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PROG
| (MAGMA) [Floor(4^(n+1)/7) : n in [1..30]]; // Vincenzo Librandi, Jun 25 2011
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CROSSREFS
| Sequence in context: A077836 A003125 A055841 * A037730 A029874 A052834
Adjacent sequences: A037518 A037519 A037520 * A037522 A037523 A037524
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KEYWORD
| nonn,base,easy
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
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