OFFSET
1,1
COMMENTS
Subset of A045940 Numbers n such that factorizations of n through n+3 have same number of primes (including multiplicities).
There are no numbers n such that n, n+1, n+2 and n+3 are products of exactly 6 primes(?).
First counterexample: 8706123. - Charles R Greathouse IV, Jan 31 2017
LINKS
D. W. Wilson, Table of n, a(n) for n = 1..10000
EXAMPLE
57967=7^3*13^2, 57968=2^4*3623, 57969=3^3*19*113, 57970=2*5*11*17*31 (all product of 5 primes, including multiplicities).
632148 is the first number such that n through n+4 are 5-almost primes.
MATHEMATICA
SequencePosition[Table[If[PrimeOmega[n]==5, 1, 0], {n, 19*10^5}], {1, 1, 1, 1}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 03 2019 *)
PROG
(PARI) isok(n) = (bigomega(n) == 5) && (bigomega(n+1) == 5) && (bigomega(n+2) == 5) && (bigomega(n+3) == 5); \\ Michel Marcus, Oct 11 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 05 2006
EXTENSIONS
More terms from Michel Marcus, Oct 11 2013
STATUS
approved