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!)
 A185032 Initial term of first run of exactly n consecutive numbers with 3 distinct prime factors. 2
 30, 230, 644, 1308, 2664, 6850, 10280, 39693, 44360, 48919, 218972, 534078, 2699915, 526095, 17233173, 127890362, 29138958036, 146216247221 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The number of distinct prime factors is A001221. If any following terms exist, they are greater than 10^13. Eggleton and MacDougall show that there are no more than 59 terms in this sequence. a(19) <= 7523987244435061. - Donovan Johnson, Jul 08 2013 LINKS Roger B. Eggleton and James A. MacDougall, Consecutive integers with equally many principal divisors, Math. Mag. 81 (2008), 235-248. R. B. Eggleton, J. S. Kimberley, and J. A. MacDougall, Principal divisor ranks of the first trillion positive integers, NOVA: The University of Newcastleâ€™s Digital Research Repository (2009). EXAMPLE a(14) < a(13) because the first run of 13 consecutive integers i with A001221(i)=3 is not a maximal run. CROSSREFS Cf. A080569, A064709, and A185042. Sequence in context: A156372 A064241 A080569 * A291466 A246892 A246893 Adjacent sequences:  A185029 A185030 A185031 * A185033 A185034 A185035 KEYWORD nonn,fini AUTHOR R. B. Eggleton, Jason Kimberley, and J. A. MacDougall, Apr 12 2011 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 24 07:28 EDT 2020. Contains 337317 sequences. (Running on oeis4.)