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Search: id:A140132
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| A140132 |
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a(n)=Sum_digits{a(n-1)+a(n-2)+Sum_digits[a(n-1)]+Sum_digits[a(n-2)]}, with a(0)=0 and a(1)=1. |
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2
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| 0, 1, 2, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7, 8, 3, 4, 5, 9, 10, 11, 6, 7
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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After the first three terms the sequence is periodic: 6,7,8,3,4,5,9,10,11.
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FORMULA
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a(n)=(1/12)*{-3*(n mod 9)+[(n+1) mod 9]+[(n+2) mod 9]+9*[(n+3) mod 9]+[(n+4) mod 9]+[(n+5) mod 9]+9*[(n+6) mod 9]+[(n+7) mod 9]+[(n+8) mod 9]}-9*{[C(2*n,n) mod 2]+[C((n+1)^2,n+3) mod 2]+[C((n+12)^4,n+14) mod 2]}, with n>=0
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MAPLE
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P:=proc(n) local a, b, i, k, w, x, y; a:=0; b:=1; print(a); print(b); for i from 1 by 1 to n do w:=0; k:=a; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; x:=0; k:=b; while k>0 do x:=x+k-(trunc(k/10)*10); k:=trunc(k/10); od; c:=b; y:=0; k:=a+b+w+x; while k>0 do y:=y+k-(trunc(k/10)*10); k:=trunc(k/10); od; a:=b; b:=y; print(y); od; end: P(100);
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CROSSREFS
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Cf. A016052, A047892, A047897-A047900, A047902, A047903, A055263, A134268, A135210, A140131.
Sequence in context: A061352 A039926 A035569 this_sequence A096909 A073005 A091942
Adjacent sequences: A140129 A140130 A140131 this_sequence A140133 A140134 A140135
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KEYWORD
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easy,nonn
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AUTHOR
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Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), May 09 2008
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