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 A136138 a(n+1)=sopfr(4a(n)+1), with sopfr=A001414. Finishes with the cycle (34, 137, 67, 269, 362, 36). 3
 1, 5, 10, 41, 19, 18, 73, 293, 43, 173, 24, 97, 389, 179, 242, 39, 157, 54, 38, 23, 34, 137, 67, 269, 362, 36, 34 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS In the class of recurrence sequences a(n+1)=sopfr(C*a(n)+D), with C=4, D=1. It is a simple example where it finishes with a nontrivial cycle. LINKS Table of n, a(n) for n=0..26. FORMULA a(n+1) = A001414(4*a(n)+1). MATHEMATICA sopfr = Function[x, Plus @@ Map[Times @@ # &, FactorInteger[x]]]; NestList[sopfr[4# + 1] &, 1, 40] NestList[Total[Times@@@FactorInteger[4*#+1]]&, 1, 30] (* Harvey P. Dale, Sep 23 2019 *) CROSSREFS Cf. A136136, A136137. Sequence in context: A001692 A038070 A364738 * A321307 A270288 A271805 Adjacent sequences: A136135 A136136 A136137 * A136139 A136140 A136141 KEYWORD fini,nonn AUTHOR Carlos Alves, Dec 16 2007 STATUS approved

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Last modified July 22 13:05 EDT 2024. Contains 374499 sequences. (Running on oeis4.)