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A128216
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a(1)=a(2)=1. a(n+1) = a(n) + a(smallest prime dividing n).
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1
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1, 1, 2, 4, 5, 10, 11, 22, 23, 25, 26, 52, 53, 106, 107, 109, 110, 220, 221, 442, 443, 445, 446, 892, 893, 898, 899, 901, 902, 1804, 1805, 3610, 3611, 3613, 3614, 3619, 3620, 7240, 7241, 7243, 7244, 14488, 14489, 28978, 28979, 28981, 28982, 57964, 57965
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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EXAMPLE
| The smallest prime dividing 12 is 2. So a(13) = a(12) + a(2) = 52 + 1 = 53.
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MAPLE
| with(numtheory): a[1]:=1:a[2]:=1:for n from 2 to 55 do a[n+1]:=a[n]+a[factorset(n)[1]] od: seq(a[n], n=1..55); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 07 2007
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CROSSREFS
| Cf. A128215, A020639.
Sequence in context: A057762 A109511 A018339 * A080735 A091856 A083416
Adjacent sequences: A128213 A128214 A128215 * A128217 A128218 A128219
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Feb 19 2007
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 07 2007
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