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Search: id:A070959
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| A070959 |
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First minimum value > 0 of the form x^3-k^2 when k > n^3. |
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+0
2
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| 4, 4, 39, 13, 152, 28, 391, 49, 804, 76, 1439, 109, 2344, 148, 3567, 193, 5156, 244, 7159, 301, 9624, 364, 12599, 433, 16132, 508, 20271, 589, 25064, 676, 30559, 769, 36804, 868, 43847, 973, 51736, 1084, 60519, 1201, 70244, 1324, 80959, 1453, 92712
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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Let k be the smallest integer>n^3 such that A070923(k-1)> A070923(k) and such that A070923(k)<A070923(k+1), then a(n)= A070923(k); for n>=1 a(2n-1) = 8n^3-9n^2+6n-1, a(2n)=3n^2+1
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EXAMPLE
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Let n=2 then n^3=8 and A070923(9)= 44, A070923(10)=25, A070923(11)=4, A070923(12)=72 so the first minimum is 4, hence a(2)=4
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PROGRAM
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(PARI) for(n=1, 100, s=n^3+1; while(ceil(s^(2/3))^3-s^2>ceil((s+1)^(2/3))^3-(s+1)^2, s++); print1(ceil(s^(2/3))^3-s^2, ", "))
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CROSSREFS
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Cf. A070923.
Sequence in context: A129357 A100303 A111882 this_sequence A125066 A016498 A082794
Adjacent sequences: A070956 A070957 A070958 this_sequence A070960 A070961 A070962
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), May 25 2002
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