The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A090699 Decimal expansion of the Erdos-Szekeres constant zeta(3/2)/zeta(3). 4
 2, 1, 7, 3, 2, 5, 4, 3, 1, 2, 5, 1, 9, 5, 5, 4, 1, 3, 8, 2, 3, 7, 0, 8, 9, 8, 4, 0, 4, 3, 8, 2, 2, 3, 7, 2, 2, 9, 0, 6, 7, 1, 1, 3, 2, 9, 1, 3, 1, 6, 6, 0, 8, 5, 6, 7, 4, 9, 1, 7, 5, 7, 5, 8, 9, 6, 7, 0, 5, 9, 6, 6, 1, 7, 2, 6, 6, 4, 4, 4, 6, 8, 2, 0, 3, 7, 8, 5, 7, 2, 7, 8, 3, 8, 3, 1, 7, 6, 5, 1, 0, 2, 6, 6, 4 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Let N(x) denotes the number of 2-full integers not exceeding x. Then limit x ->infty N(x)/sqrt(x)=zeta(3/2)/zeta(3). Also related to Niven's constant. REFERENCES S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 112-114. LINKS S. W. Golomb, Powerful numbers, Amer. Math. Monthly, Vol. 77 (1970), 848-852. Ivan Niven, Averages of Exponents in Factoring Integers, Proc. Amer. Math. Soc., Vol. 22, No. 2 (1969), pp. 356-360. FORMULA Product_{p prime} (1+1/p^(3/2)) = zeta(3/2)/zeta(3). - T. D. Noe, May 03 2006 Equals lim_{n->oo} (Sum_{k=1..n} A051904(k) - n)/sqrt(n) (Niven, 1969). EXAMPLE zeta(3/2)/zeta(3) = 2.17325431251955413823708984... MATHEMATICA RealDigits[N[Zeta[3/2]/Zeta[3], 150]][[1]] (* T. D. Noe, May 03 2006 *) PROG (PARI) zeta(3/2)/zeta(3) \\ Michel Marcus, Oct 06 2017 CROSSREFS Cf. A001694 (powerful numbers), A102834 (nonsquare powerful numbers). Cf. A033150, A051904. Sequence in context: A320579 A091370 A125697 * A214550 A120903 A180335 Adjacent sequences:  A090696 A090697 A090698 * A090700 A090701 A090702 KEYWORD cons,nonn AUTHOR Benoit Cloitre, Jan 14 2004 EXTENSIONS Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 16 2007 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 23 09:03 EDT 2020. Contains 337298 sequences. (Running on oeis4.)