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A028389 The 5x + 1 sequence beginning at 7. 1
7, 36, 18, 9, 46, 23, 116, 58, 29, 146, 73, 366, 183, 916, 458, 229, 1146, 573, 2866, 1433, 7166, 3583, 17916, 8958, 4479, 22396, 11198, 5599, 27996, 13998, 6999, 34996, 17498, 8749, 43746, 21873, 109366, 54683, 273416, 136708, 68354, 34177, 170886, 85443, 427216 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..10000

FORMULA

a(0) = 7; a(n) = 5*a(n-1) + 1 if a(n-1) is odd, a(n) = a(n-1)/2 otherwise.

MAPLE

f := proc(n) option remember; if n = 0 then 7 elif f(n-1) mod 2 = 0 then f(n-1)/2 else 5*f(n-1)+1; fi; end; seq(f(n), n=0..50);

MATHEMATICA

a[0] = 7; a[n_] := a[n] = If[OddQ[a[n-1]], 5 a[n-1] + 1, a[n-1]/2];

a /@ Range[0, 50] (* Jean-Fran├žois Alcover, Nov 03 2020 *)

CROSSREFS

Cf. A259207, A328010, A328011.

Sequence in context: A231511 A078235 A197555 * A041603 A176543 A018199

Adjacent sequences:  A028386 A028387 A028388 * A028390 A028391 A028392

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dean Hickerson

EXTENSIONS

Named edited by Andrew Howroyd, Aug 21 2020

STATUS

approved

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Last modified April 22 07:26 EDT 2021. Contains 343163 sequences. (Running on oeis4.)