A369898 Numbers k such that k and k + 1 each have 9 prime divisors, counted with multiplicity.
203391, 698624, 1245375, 1942784, 2176064, 2282175, 2536191, 2858624, 2953664, 3282687, 3560192, 3655935, 3914000, 4068224, 4135616, 4205600, 4244967, 4586624, 4695488, 4744575, 4991679, 5055615, 5450624, 5475519, 5519744, 6141824, 6246800, 6410096, 6655040, 6660224, 6753375, 6816879, 6862400
Offset: 1
Keywords
Examples
a(3) = 1245375 is a term because 1245375 = 3^5 * 5^3 * 41 and 1245376 = 2^6 * 11 * 29 * 61 each have 9 prime factors, counted with multiplicity.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
-
Maple
with(priqueue): R:= NULL: count:= 0: initialize(Q); r:= 0: insert([-2^9, [2$9]], Q); while count < 40 do T:= extract(Q); if -T[1] = r + 1 then R:= R, r; count:= count+1; fi; r:= -T[1]; p:= T[2][-1]; q:= nextprime(p); for i from 9 to 1 by -1 while T[2][i] = p do insert([-r*(q/p)^(10-i), [op(T[2][1..i-1]), q$(10-i)]], Q); od od: R;
Comments