login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A288517 Least integer k such that A001358(k) + A001358(k+1) is the product of exactly n prime factors (counting multiplicity). 1

%I #18 Jul 26 2017 23:18:02

%S 3,1,28,4,19,39,48,89,120,551,447,589,3707,10137,21644,28456,22998,

%T 44494,86132,166930,703448,628371,1220814,1608668,11153853,6091437,

%U 56676014,268389220,146153797,193010987,916382785,738246947,4702317172,2830095027,12627951809

%N Least integer k such that A001358(k) + A001358(k+1) is the product of exactly n prime factors (counting multiplicity).

%H Charles R Greathouse IV, <a href="/A288517/b288517.txt">Table of n, a(n) for n = 1..50</a>

%e n=1: k=3, A001358(3) + A001358(4) = 9 + 10 = 19 = A000040(8) (8th prime),

%e n=2: k=1, A001358(1)+A001358(2) = 4+6 = 10 = 2*5 = A001358(4) (4th semiprime),

%e n=11: k=447, A001358(447)+A001358(448) = 1535+1537 = 3072 = 2^10*3 = A069272(2) (2nd 11-almost prime).

%Y Cf. A000040, A001358, A014612, A014614, A046306, A046308, A046310, A046312, A046314, A069272.

%K nonn

%O 1,1

%A _Zak Seidov_, Jun 10 2017

%E a(21)-a(35) from _Charles R Greathouse IV_, Jun 10 2017

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 4 21:18 EDT 2024. Contains 372257 sequences. (Running on oeis4.)