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.

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

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)>7||omega(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