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A123201 Numbers n such that factorizations of n..n+7 have same number of primes (including multiplicities). 4
3405122, 3405123, 6612470, 8360103, 8520321, 9306710, 10762407, 12788342, 12788343, 15212151, 15531110, 16890901, 17521382, 17521383, 21991382, 21991383, 22715270, 22715271, 22841702, 22841703, 22914722, 22914723 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that because 3405130 = 2*5*167*2039 is also 4-almost prime, 3405122 is the first n such that numbers n..n+8 are products of the same number N of primes (N=4).

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..10000

EXAMPLE

3405122 = 2*7*29*8387, 3405123 = 3^2*19*19913, 3405124 = 2^2*127*6703, 3405125 = 5^3*27241, 3405126 = 2*3*59*9619, 3405127 = 11*23*43*313, 3405128 = 2^3*425641, 3405129 = 3*7*13*12473 all 4-almost primes.

PROG

(PARI) c=0; p1=0; for(n=2, 10^8, p2=bigomega(n); if(p1==p2, c++; if(c>=7, print1(n-7 ", ")), c=0; p1=p2)) /* Donovan Johnson, Mar 20 2013 */

CROSSREFS

Cf. A045940, A045941, A045942, A123103.

Sequence in context: A206382 A114682 A157106 * A258517 A258510 A254997

Adjacent sequences:  A123198 A123199 A123200 * A123202 A123203 A123204

KEYWORD

nonn

AUTHOR

Zak Seidov, Nov 05 2006

EXTENSIONS

a(7)-a(22) from Donovan Johnson, Apr 09 2010

STATUS

approved

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Last modified May 16 19:46 EDT 2021. Contains 343951 sequences. (Running on oeis4.)