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Search: id:A089182
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| A089182 |
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Prime digit palindromes 2,...,23577532 continued by adding 10^(n-k) and 10^(k-1) times prime(k). |
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+0
2
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| 2, 22, 232, 2332, 23532, 235532, 2357532, 23577532, 235817532, 2358217532, 23582417532, 235824417532, 2358248417532, 23582488417532, 235824908417532, 2358249108417532, 23582491508417532, 235824915508417532
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Original definition: Overlapping prime-based palindromic sequence.
Only the first 8 terms are truely palindromes: a modulo 10 version of this would work with a limited digit set {1,2,3,5,7,9} with 2 and 5 only occuring as 1st and 3rd digit to either side.
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FORMULA
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a(n)=sum( k=1...[n/2], prime(k)*(10^(n-k)+10^(k-1)) + (n%2)*prime((n+1)/2)*10^[n/2], where [x]=floor(x) and n%2=0 for n even, 1 for n odd. - M. F. Hasler, Apr 06 2009
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MATHEMATICA
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a[m_]=Delete[Table[If [ Floor[m/2]-n>=0, Prime[ n], Prime[m-n]], {n, 1, m}], m] b=Table[Sum[a[m][[i]]*10^(i-1), {i, 1, m-1}], {m, 2, digits}]
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CROSSREFS
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Cf. A007907, A138140.
Sequence in context: A002276 A112893 A086855 this_sequence A138140 A151617 A082777
Adjacent sequences: A089179 A089180 A089181 this_sequence A089183 A089184 A089185
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KEYWORD
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nonn,base
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Dec 07 2003
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EXTENSIONS
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Edited by M. F. Hasler (MHasler(AT)univ-ag.fr), Apr 06 2009
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