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 A214892 Conway's subprime Fibonacci sequence starting with (4,1). 10
 4, 1, 5, 3, 4, 7, 11, 9, 10, 19, 29, 24, 53, 11, 32, 43, 25, 34, 59, 31, 45, 38, 83, 11, 47, 29, 38, 67, 35, 51, 43, 47, 45, 46, 13, 59, 36, 19, 11, 15, 13, 14, 9, 23, 16, 13, 29, 21, 25, 23, 24, 47, 71, 59, 65, 62, 127, 63, 95, 79, 87, 83, 85, 84, 13, 97, 55, 76, 131, 69, 100, 13, 113 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Similar to the Fibonacci recursion starting with (4, 1), but each new nonprime term is divided by its least prime factor. Sequence enters a loop of length 136 after 8 terms on reaching (11, 9). LINKS Wouter Meeussen, Table of n, a(n) for n = 1..144 Richard K. Guy, Tanya Khovanova and Julian Salazar, Conway's subprime Fibonacci sequences, arXiv:1207.5099 [math.NT], 2012-2014. MATHEMATICA (* see A214674 *) a[1] = 4; a[2] = 1; a[n_] := a[n] = If[an = a[n-2]+a[n-1]; PrimeQ[an], an, an/FactorInteger[an][[1, 1]]]; Array[a, 80] (* Jean-François Alcover, Nov 17 2018 *) CROSSREFS Cf. A000045, A020639, A175723, A214551, A014682, A214674, A214892-A214898. Sequence in context: A115210 A199150 A329215 * A030352 A212643 A104571 Adjacent sequences:  A214889 A214890 A214891 * A214893 A214894 A214895 KEYWORD nonn AUTHOR Wouter Meeussen, Jul 29 2012 STATUS approved

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Last modified September 22 22:38 EDT 2021. Contains 347609 sequences. (Running on oeis4.)