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Search: id:A128201
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| A128201 |
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Union of squares and the odd numbers. |
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+0
5
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| 1, 3, 4, 5, 7, 9, 11, 13, 15, 16, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 36, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 64, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 100, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Range of A128200.
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LINKS
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R. Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) = f(n,1,1,2) where f(n,i,m,x) = if i=n then m else if m+1=x^2 then f(n,i+1,m+1,x) else if m+1>x^2 then f(n,i+1,m+1,x+2) else f(n,i+1,m+2,x).
Set R=2n-ROUND(SQRT(2n),0), then a(n)=ITE(ROUND(SQRT(R),0)^2=R,R,ITE((R mod 2)=1,R,R+1)) [From Gerald Hillier (adr.rabbicat(AT)gmail.com), Feb 03 2009]
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CROSSREFS
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Partial sums given by A157130 [From Gerald Hillier (adr.rabbicat(AT)gmail.com), Feb 25 2009]
Sequence in context: A047501 A035242 A161153 this_sequence A096262 A049646 A033556
Adjacent sequences: A128198 A128199 A128200 this_sequence A128202 A128203 A128204
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 04 2007
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