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A167182 a(n) = Product_{i=1..n-1} a(i) with a(1) = 2, a(2) = 4. 3
2, 4, 8, 64, 4096, 16777216, 281474976710656, 79228162514264337593543950336, 6277101735386680763835789423207666416102355444464034512896 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

b(0) = 3; b(n+1) is the smallest number not in the sequence such that b(n+1) - Product_{i=0..n} b(i) divides b(n+1) + Product_{i=0..n} b(i). Then, b(n+1) = a(n) for n > 0. - Derek Orr, Jan 04 2015

Term a(13) has 925 decimal digits; a(14) has 1850 decimal digits. - Michael De Vlieger, Jan 07 2015

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..13

FORMULA

a(n) = (a(n-1))^2 for n > 3.

a(n) = 2^A098011(n+1). - R. J. Mathar, Apr 22 2010

MATHEMATICA

a167182[n_] := Block[{t = {2, 4}, f}, AppendTo[t, Times @@ t]; f[x_] := t[[x - 1]]^2; Do[AppendTo[t, f[i]], {i, 4, n}]; t]; a167182[9] (* Michael De Vlieger, Jan 07 2015 *)

Join[{2, 4}, NestList[#^2&, 8, 10]] (* Harvey P. Dale, Nov 30 2019 *)

CROSSREFS

Cf. A165426.

Sequence in context: A067507 A320898 A068994 * A058345 A093843 A270372

Adjacent sequences:  A167179 A167180 A167181 * A167183 A167184 A167185

KEYWORD

nonn

AUTHOR

Giovanni Teofilatto, Oct 29 2009

EXTENSIONS

Definition corrected by R. J. Mathar, Apr 22 2010

More terms from Vincenzo Librandi, Apr 25 2010

STATUS

approved

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Last modified August 10 02:28 EDT 2020. Contains 336367 sequences. (Running on oeis4.)