

A005166


a(0) = 1; a(n) = (1 + a(0)^3 + ... + a(n1)^3)/n (not always integral!).
(Formerly M1551)


6




OFFSET

0,2


COMMENTS

Terms are integers until n=A097398(2,2)=89.
Guy states that by computing the sequence modulo 89 it is easy to show that a(89) is not integral.  T. D. Noe, Sep 17 2007


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

T. D. Noe, Table of n, a(n) for n=0..9
R. K. Guy, Letter to N. J. A. Sloane, Sep 25 1986.
R. K. Guy, The strong law of small numbers. Amer. Math. Monthly 95 (1988), no. 8, 697712.
R. K. Guy, The strong law of small numbers. Amer. Math. Monthly 95 (1988), no. 8, 697712. [Annotated scanned copy]
N. Lygeros & M. Mizony, Study of primality of terms of a_k(n)=(1+(sum from 1 to n1)(a_k(i)^k))/(n1) [dead link]
Eric Weisstein's World of Mathematics, Goebel's Sequence.


CROSSREFS

Cf. A003504, A005167.
Cf. A108394
Sequence in context: A334252 A307147 A056680 * A121621 A225147 A119715
Adjacent sequences: A005163 A005164 A005165 * A005167 A005168 A005169


KEYWORD

nonn,easy,nice


AUTHOR

N. J. A. Sloane.


STATUS

approved



