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Search: id:A065132
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| A065132 |
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Arithmetic mean of first n terms of A008472 is an integer. |
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+0
2
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| 2, 13, 134, 167, 2239, 62268, 75255, 135681, 439867, 18139940, 23671044, 40892256, 312083956, 724031017, 1990127567, 2144843867, 2588619526, 7439533243, 15054156002
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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A024924(n)/n is integer, where A024924(n+1)=A024924(n)+A008472(n) and A008472 is sum of distinct primes dividing n.
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EXAMPLE
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Sum of first 13 terms of A008472 gives A024924(13) = 65 which is divisible with n = 13, so 13 is here: 0+2+3+2+5+5+7+2+3+7+11+5+13 = 65 = 13*5 = A024924(13)
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MATHEMATICA
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s=0; Do[s=s+sp[n]; If[IntegerQ[n/25000], Print[n]]; If[IntegerQ[s/n], Print[{n, s, s/n}]], {n, 2, 4000000}] where sp[n]=A008472(n).
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CROSSREFS
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A024924, A008472.
Sequence in context: A085882 A041509 A079165 this_sequence A047856 A152059 A132063
Adjacent sequences: A065129 A065130 A065131 this_sequence A065133 A065134 A065135
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KEYWORD
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nonn,new
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Oct 15 2001
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EXTENSIONS
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a(10)-a(19) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 22 2009
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