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Search: id:A083055
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A083055 a(n) = cardinality{ k<=n / A083054(k)=1}. +0
4
1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 14, 14, 14, 15, 15, 16, 16, 16, 16, 16, 17, 17, 18, 18, 18, 18, 18, 19, 19, 20, 20, 20, 21, 21, 22, 22, 22, 22, 22, 23, 23, 24, 24, 24, 24, 24, 25, 25 (list; graph; listen)
OFFSET

1,6

LINKS

Boris Gourevitch, Graph of A083057

FORMULA

a(n) = n/3 + O(n) (it seems O(n) could be replaced with O(log(n)))

PROGRAM

(PARI) {a(n)=if(n<1, 0, sum(k=1, n, sqrtint(3*k^2)-3*sqrtint(k^2\3)==1))} /* Michael Somos Aug 31 2006 */

CROSSREFS

Cf. A083038, A083054, A083056, A083057.

Adjacent sequences: A083052 A083053 A083054 this_sequence A083056 A083057 A083058

Sequence in context: A085269 A054071 A028827 this_sequence A121828 A057357 A029123

KEYWORD

nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 18 2003

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Last modified October 9 14:06 EDT 2008. Contains 144831 sequences.


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