

A001598


Number of terms in {b(1)..b(n)} relatively prime to b(n), where b(n) = A001597(n).
(Formerly M2244 N0891)


1



1, 1, 1, 3, 2, 5, 5, 4, 2, 9, 5, 8, 5, 13, 12, 8, 5, 17, 8, 6, 11, 14, 11, 23, 7, 23, 26, 11, 16, 14, 15, 31, 10, 28, 16, 24, 15, 37, 9, 39, 16, 20, 27, 20, 31, 14, 43, 47, 23, 32, 20, 51, 17, 14, 54, 24, 30, 28, 27, 40, 57, 61, 20, 56, 26, 42, 30, 28, 68, 22
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,4


REFERENCES

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
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 = 1..1000
H. W. Gould, Problem H170, Fib. Quart., 8 (1970), p. 268.


MATHEMATICA

nn = 10^4; t = Join[{1}, Union[Flatten[Table[n^i, {i, Prime[Range[PrimePi[Log[2, nn]]]]}, {n, 2, nn^(1/i)}]]]]; Table[Count[GCD[Take[t, n], t[[n]]], 1], {n, Length[t]}] (* T. D. Noe, Aug 09 2012 *)


CROSSREFS

Sequence in context: A132778 A182289 A127738 * A141297 A303917 A186929
Adjacent sequences: A001595 A001596 A001597 * A001599 A001600 A001601


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane.


EXTENSIONS

a(1) added by T. D. Noe, Aug 09 2012


STATUS

approved



