A337219 a(n) is the least positive number k such that 3^n+k has n prime factors counted with multiplicity.

2, 1, 1, 3, 9, 7, 21, 63, 157, 471, 5, 15, 45, 135, 405, 1215, 3645, 10935, 32805, 98415, 295245, 885735, 2657205, 4409119, 2741597, 8224791, 16285765, 15302863, 45908589, 137725767, 77632981, 232898943, 161825917, 485477751, 1456433253, 3027122479, 1565174669

Offset

1,1

Links

David A. Corneth, Table of n, a(n) for n = 1..56

Mathematica

a[n_] := Module[{k = 1}, While[PrimeOmega[3^n + k] != n, k++]; k]; Array[a, 20] (* Amiram Eldar, Sep 18 2020 *)

Prog

(PARI) a(n) = for(k=1, oo, if(bigomega(3^n+k)==n, return(k))); \\ Daniel Suteu, Oct 17 2020

Crossrefs

Cf. A078843.

Sequence in context: A235453 A219206 A077385 * A220898 A336163 A066013

Adjacent sequences: A337216 A337217 A337218 * A337220 A337221 A337222

Keyword

nonn

Author

Zak Seidov, Sep 14 2020

Extensions

a(27)-a(37) from Daniel Suteu, Sep 14 2020

Definition edited by Zak Seidov, Oct 17 2020

Status

approved