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A086560 Start of first run of n successive numbers in which i-th number has exactly i distinct prime divisors for i = 1..n. 3
2, 5, 64, 1867, 491851, 17681491, 35565206671, 43194825904693 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 64, p. 23, Ellipses, Paris 2008.

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

a(3) = 64, as 64 has 1, 65 has 2 and 66 has 3 prime divisors: 64 = 2^6, 65 = 5*13 and 66 = 2*3*11

CROSSREFS

Cf. A072875.

Sequence in context: A012978 A012949 A076630 * A133004 A175169 A066933

Adjacent sequences:  A086557 A086558 A086559 * A086561 A086562 A086563

KEYWORD

more,nonn

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 30 2003

EXTENSIONS

More terms from Don Reble (djr(AT)nk.ca), Sep 13 2003

a(7) from Donovan Johnson, Mar 06 2008

a(8) from Donovan Johnson, Jul 19 2011

STATUS

approved

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Last modified May 24 07:09 EDT 2013. Contains 225617 sequences.