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Search: id:A065131
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| A065131 |
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Arithmetic mean of first n terms of A001414 is an integer. |
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+0
1
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| 2, 8, 18, 26, 27, 53, 344, 539, 1221, 6869, 7271, 10753, 17742, 33289, 59688, 156649, 949350, 2291181, 3115026, 3283468
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OFFSET
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1,1
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FORMULA
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A025281(n)/n is integer, where A025281(n+1)=A025281(n)+A001414(n) and A001414 is sum of primes dividing n (with repetition).
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EXAMPLE
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Sum of first 18 terms of A001414 gives A025281(18)=126 which is divisible with n=18, so 18 is here: 0+2+3+4+5+5+7+6+6+7+11+7+13+9+8+8+17+8=126=7*18,
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MATHEMATICA
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s=0; Do[s=s+lg[n]; If[IntegerQ[n/25000], Print[n]]; If[IntegerQ[s/n], Print[{n, s, s/n}]], {n, 2, 2000000}] where lg[n]=A001414(n).
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CROSSREFS
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A025281, A001414.
Sequence in context: A117612 A109136 A137392 this_sequence A063581 A055044 A067051
Adjacent sequences: A065128 A065129 A065130 this_sequence A065132 A065133 A065134
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Oct 15 2001
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