This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A062090 a(1) = 1, a(n) = smallest odd number that does not divide the product of all previous terms. 11
 1, 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS In A050150 but not here: [729, 15625, 59049, 117649, 531441]; here but not in A050150: [1, 6561, 390625]. - Klaus Brockhaus, Nov 01 2001 LINKS T. D. Noe, Table of n, a(n) for n=1..1000 FORMULA Numbers of the form p^(2^k) where p is an odd prime and k is a nonnegative integer. EXAMPLE After 13 the next term is 17 (not 15) as 15 = 3*5 divides the product of all the previous terms. MATHEMATICA a = {1}; Do[b = Apply[ Times, a]; k = 1; While[ IntegerQ[b/k], k += 2]; a = Append[a, k], { n, 2, 60} ]; a PROG (Haskell) a062090 n = a062090_list !! (n-1) a062090_list = f [1, 3 ..] [] where    f (x:xs) ys = g x ys where      g _ []     = x : f xs (x : ys)      g 1 _      = f xs ys      g z (v:vs) = g (z `div` gcd z v) vs -- Reinhard Zumkeller, Aug 16 2013 CROSSREFS Cf. A026477, A062091, A050150 (a different sequence). Sequence in context: A080429 A326581 A050150 * A172095 A309361 A133854 Adjacent sequences:  A062087 A062088 A062089 * A062091 A062092 A062093 KEYWORD nonn,easy,nice AUTHOR Amarnath Murthy, Jun 16 2001 EXTENSIONS Corrected and extended by Dean Hickerson, Jul 10 2001 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 21 19:39 EDT 2019. Contains 327279 sequences. (Running on oeis4.)