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 A258056 3x + 1 sequence starting at 75. 2
 75, 226, 113, 340, 170, 85, 256, 128, 64, 32, 16, 8, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) gives the value obtained after n iterations of the Collatz function starting at 75. - Daniel Forgues, May 19 2015 a(n) = 1 for the first time with n = 14 (14 iterations); at this point, we get the trivial (1, 4, 2) cycle... (A153727). - Daniel Forgues, May 22 2015 LINKS FORMULA a(0) = 75; a(n) = 3*a(n - 1) + 1 if a(n - 1) is odd, a(n) = a(n - 1)/2 otherwise. EXAMPLE 75 is odd, so it's followed by 3*75 + 1 = 226. 226 is even, so it's followed by 226/2 = 113. MATHEMATICA NestList[If[EvenQ[#], #/2, 3# + 1] &, 75, 100] PROG (MAGMA) [n eq 1 select 75 else IsOdd(Self(n-1)) select 3*Self(n-1)+1 else Self(n-1) div 2: n in [1..80]]; // Vincenzo Librandi, May 18 2015 (Sage) def collatz(start):     a = start     while True:         yield a         a = 3*a + 1 if is_odd(a) else a/2 A258056 = collatz(75) [next(A258056) for _ in range(60)] # Peter Luschny, May 22 2015 CROSSREFS Cf. A033478, A153727. Sequence in context: A003503 A201916 A098230 * A174685 A158742 A292313 Adjacent sequences:  A258053 A258054 A258055 * A258057 A258058 A258059 KEYWORD nonn,easy AUTHOR Alonso del Arte, May 17 2015 STATUS approved

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Last modified April 10 14:07 EDT 2021. Contains 342845 sequences. (Running on oeis4.)