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A058974
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a(n) = 0 if n = 1 or a prime, otherwise a(n) = s + a(s) iterated until no change occurs, where s (A008472) is sum of distinct primes dividing n.
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1
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0, 0, 0, 2, 0, 5, 0, 2, 3, 7, 0, 5, 0, 12, 10, 2, 0, 5, 0, 7, 17, 13, 0, 5, 5, 25, 3, 12, 0, 17, 0, 2, 26, 19, 17, 5, 0, 38, 18, 7, 0, 17, 0, 13, 10, 30, 0, 5, 7, 7, 27, 25, 0, 5, 18, 12, 35, 31, 0, 17, 0, 59, 17, 2, 23, 18, 0, 19, 51, 26, 0, 5, 0, 57, 10, 38, 23
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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REFERENCES
| E. N. Gilbert, An interesting property of 38, unpublished, circa 1992. Shows that 38 is the only solution of a(n) = n.
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MAPLE
| f := proc(n) option remember; local i, j, k, t1, t2; if n = 1 or isprime(n) then 0 else A008472(n) + f(A008472(n)); fi; end;
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MATHEMATICA
| f[n_Integer] := If[n == 1 || PrimeQ[n], 0, Plus @@ First[ Transpose[ FactorInteger[n]]]]; Table[Plus @@ Drop[ FixedPointList[f, n], 1], {n, 1, 80}]
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CROSSREFS
| Cf. A008472.
Sequence in context: A071090 A105221 A061376 * A019962 A086131 A104755
Adjacent sequences: A058971 A058972 A058973 * A058975 A058976 A058977
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jan 15 2001
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