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Search: id:A056487
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| A056487 |
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a(n)=5^(n/2) for n even, a(n)=3*5^((n-1)/2) for n even. |
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+0
2
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| 1, 3, 5, 15, 25, 75, 125, 375, 625, 1875, 3125, 9375, 15625, 46875, 78125, 234375, 390625, 1171875, 1953125, 5859375, 9765625, 29296875, 48828125, 146484375, 244140625, 732421875, 1220703125, 3662109375
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Number of periodic palindromes using a maximum of five different symbols. For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome.
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REFERENCES
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M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.
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FORMULA
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a(n+2)=5a(n), a(0)=1, a(2)=3.
Binomial transform of A087205. Binomial transform is A087206. - Paul Barry (pbarry(AT)wit.ie), Aug 25 2003
G.f.: (1+3x)/(1-5x^2); a(n)=5^(n/2)(1/2+3sqrt(5)/10+(1/2-3sqrt(5)/10)(-1)^n). - Paul Barry (pbarry(AT)wit.ie), Mar 19 2004
2nd inverse binomial transform of Fib(3n+2). - Paul Barry (pbarry(AT)wit.ie), Apr 16 2004
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CROSSREFS
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Cf. A029744, A038754, A056451.
Sequence in context: A108814 A018272 A018421 this_sequence A111386 A053351 A051044
Adjacent sequences: A056484 A056485 A056486 this_sequence A056488 A056489 A056490
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KEYWORD
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nonn
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AUTHOR
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Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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