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Search: id:A102883
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| A102883 |
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Terms which share a divisor greater than 1 with the value formed by adding them to the sum of their divisors less than or equal to their square roots. |
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+0
2
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| 6, 12, 18, 24, 28, 36, 40, 42, 45, 48, 50, 54, 56, 60, 66, 70, 72, 75, 78, 80, 90, 96, 98, 100, 102, 110, 112, 114, 117, 120, 126, 130, 132, 135, 138, 144, 150, 154, 156, 160, 162, 165, 170, 174, 176, 180, 186, 190, 192, 196, 198, 200, 204, 208, 210, 216, 220
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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At first glance it appears that all multiples of 6 are included in this sequence, but a number of them are excluded (such as 5*6 and 14*6.) See A102884 for a list of multiples of 6 not included in this sequence.
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EXAMPLE
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a(3) = 18 because the divisors of 18 less than or equal to its square root are 1, 2 and 3. 18+1+2+3 = 24 and GCD(18,24) = 6 which is greater than 1. 18 is the third term which satisfies this requirement.
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MAPLE
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compute := proc (n) local m, a; m := n; for a to n^.5 do if `mod`(n, a) = 0 then m := m+a end if end do; m end proc L:=[]; for i from 1 to 2500 do; if i>0 then; x:=compute(i); if gcd(x, i) > 1 then L:=[op(L), i]; fi; fi; od; L;
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CROSSREFS
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Cf. A102884.
Sequence in context: A044846 A037917 A097603 this_sequence A044891 A121827 A126798
Adjacent sequences: A102880 A102881 A102882 this_sequence A102884 A102885 A102886
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KEYWORD
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nonn
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AUTHOR
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Chuck Seggelin (seqfan(AT)plastereddragon.com), Jan 15 2005
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