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Search: id:A140950
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| A140950 |
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Jacobsthal via Jacobthal (*). Take yesterday b(n)= 0, 1, 0, -1, 2, 0, 3, -2, 4, 0 . a(n)=b(n+1)-3b(n). |
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+0
1
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| 1, -3, -1, 5, -6, 3, -11, 10, -12, -5, 21, -22, 20, -24, 11, -43, 42, -44, 40, 42, -21
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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(*) Third part on three. a(n) generates (positive different terms,increasing order) 1, 3, 5, 6, 10, 11.
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FORMULA
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Jacobsthal numbers appears twice: 1) A001045(n+2) signed, terms 0, 1, 3, 6, 10 (A000217); 2) A001045(n+1) signed, terms 0, 2, 5, 9 (n*(n+3)/2=A000096);between them are -3; 5, -6; -11, 10, -12; which appears (opposite sign) by rows in A140503 (1, -1, 2, 3, -2, 4) square.
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CROSSREFS
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Sequence in context: A134083 A113445 A108283 this_sequence A016600 A130418 A038871
Adjacent sequences: A140947 A140948 A140949 this_sequence A140951 A140952 A140953
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KEYWORD
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sign,uned
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AUTHOR
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Paul Curtz (bpcrtz(AT)free.fr), Jul 25 2008
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