This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A072437 Numbers with no prime factors of form 4*k+3. 11
 1, 2, 4, 5, 8, 10, 13, 16, 17, 20, 25, 26, 29, 32, 34, 37, 40, 41, 50, 52, 53, 58, 61, 64, 65, 68, 73, 74, 80, 82, 85, 89, 97, 100, 101, 104, 106, 109, 113, 116, 122, 125, 128, 130, 136, 137, 145, 146, 148, 149, 157, 160, 164, 169, 170, 173, 178, 181, 185, 193, 194 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS m is a term iff A072436(m) = m. These numbers have density zero (Pollack). A005091(a(n)) = 0. - Reinhard Zumkeller, Jan 07 2013 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 119. alternate link FORMULA n>0 such that A001842(n)=0. - Benoit Cloitre, Apr 24 2003 MATHEMATICA npfQ[n_]:=Count[Transpose[FactorInteger[n]][[1]], _?(Mod[#, 4]==3&)]==0; Select[Range[200], npfQ] (* Harvey P. Dale, Nov 12 2013 *) PROG (PARI) is(n)=n==1||vecmax(factor(n)[, 1]%4)<3 \\ Charles R Greathouse IV, Apr 16 2012 (Haskell) import Data.List (elemIndices) a072437 n = a072437_list !! (n-1) a072437_list = map (+ 1) \$ elemIndices 0 a005091_list -- Reinhard Zumkeller, Jan 07 2013 CROSSREFS Cf. A004144, A002144, A002145. A097706(a(n)) = 1. Cf. A187811 (complement). Sequence in context: A268381 A186349 A144876 * A115793 A076614 A227800 Adjacent sequences:  A072434 A072435 A072436 * A072438 A072439 A072440 KEYWORD nonn AUTHOR Reinhard Zumkeller, Jun 17 2002 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.