

A321497


Numbers k such that both k and k+1 have at least 7 distinct prime factors and at least one has more than 7 distinct prime factors.


4



5163068910, 5327923964, 6564937379, 6880516929, 7122669554, 8567026545, 8814635115, 9533531370, 9611079114, 10245081314, 10246336814, 10697507414, 10783550414, 10796559410, 11260076190, 11458770609, 11992960265, 12043540145, 12172828590, 12745759740, 12850545785, 12946979220
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OFFSET

1,1


COMMENTS

Terms of A321489 (k and k+1 have at least 7 distinct prime factors) which don't satisfy the definition with "exactly 7".


LINKS

Table of n, a(n) for n=1..22.


MATHEMATICA

aQ[n_]:=Module[{v={PrimeNu[n], PrimeNu[n+1]}}, Min[v]>6 && v!={7, 7}]; Select[Range[10^10], aQ]


PROG

(PARI) is(n)=omega(n)>6&&omega(n+1)>6&&(omega(n)>7omega(n+1)>7)


CROSSREFS

Cf. A321489, A321503, A321504, A321505, A321506, A321493, A321494, A321495, A321496 (analog for 3 .. 6 factors).
Sequence in context: A338394 A017409 A017529 * A335084 A133688 A306497
Adjacent sequences: A321494 A321495 A321496 * A321498 A321499 A321500


KEYWORD

nonn


AUTHOR

Amiram Eldar and M. F. Hasler, Nov 13 2018


STATUS

approved



