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A037238
5x - 1 sequence starting at 19 (a(n+1) = a(n)/2 if a(n) is even, or 5*a(n)-1 if a(n) is odd).
2
19, 94, 47, 234, 117, 584, 292, 146, 73, 364, 182, 91, 454, 227, 1134, 567, 2834, 1417, 7084, 3542, 1771, 8854, 4427, 22134, 11067, 55334, 27667, 138334, 69167, 345834, 172917, 864584, 432292, 216146, 108073, 540364, 270182, 135091, 675454, 337727
OFFSET
1,1
COMMENTS
Reaches 4, 2, 1, 4, 2, 1, ... in 437 steps. - T. D. Noe, Mar 01 2008
MATHEMATICA
NestList[If[EvenQ[#], #/2, 5# - 1] &, 19, 100] (* Alonso del Arte, Nov 19 2020 *)
PROG
(Scala) def fiveX(n: Int): Int = n % 2 match {
case 0 => n / 2
case _ => 5 * n - 1
}
val A037238 = LazyList.iterate(19)(fiveX)
A037238.take(100).toList // Alonso del Arte, Nov 19 2020
CROSSREFS
Cf. A090691.
Sequence in context: A118294 A157098 A371532 * A109513 A173368 A041696
KEYWORD
nonn,easy
AUTHOR
Dan Goldwater (dan(AT)craftech.com)
EXTENSIONS
More terms from Erich Friedman.
Definition clarified by N. J. A. Sloane, Sep 14 2024
STATUS
approved