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Search: id:A136392
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| A136392 |
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a(n) = n*(3n-2) + (n-1)*(3n-5), n>1. |
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+0
2
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| 1, 9, 29, 61, 105, 161, 229, 309, 401, 505, 621, 749, 889, 1041, 1205, 1381, 1569, 1769, 1981, 2205, 2441, 2689, 2949, 3221, 3505, 3801, 4109, 4429, 4761, 5105, 5461, 5829, 6209, 6601, 7005, 7421, 7849, 8289, 8741, 9205, 9681, 10169
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OFFSET
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1,2
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COMMENT
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A016777 = (3n+1) with offset 0, but (3n-2) with offset 1, = 1, 4, 7, 10, 13,...
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FORMULA
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a(n) = n*(3n-2) + (n-1)*(3n-5), n>1 a(n) = n*A016777(n-1) + (n-1)*A016777(n-2). Binomial transform of [1, 8, 12, 0, 0, 0,...].
a(n)=12*n+a(n-1)-16 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009]
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EXAMPLE
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a(5) = 105 = n*(3n-2) + (n-1)*(3n-5) = 5*13 + 4*10 = 65 + 40.
For n=2, a(2)=12*2+1-16=9; n=3, a(3)=12*3+9-16=29; n=4, a(4)=12*4+29-16=61 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009]
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CROSSREFS
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Cf. A016777.
Sequence in context: A031296 A146869 A129397 this_sequence A162263 A055195 A024922
Adjacent sequences: A136389 A136390 A136391 this_sequence A136393 A136394 A136395
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KEYWORD
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nonn,new
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AUTHOR
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Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 28 2007
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EXTENSIONS
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more terms a(15)-a(42) from Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 15 2009
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