A094231 Lesser member p of sexy primes (p, p+6) such that (p+1, p+2, p+3, p+4, p+5) all have the same number of prime divisors (counted with multiplicity).

601, 42181, 70201, 240953, 277493, 414361, 418793, 619813, 632147, 637073, 723161, 732233, 739433, 761393, 781961, 879001, 934481, 979201, 1154233, 1320721, 1327673, 1357673, 1611361, 1685521, 1866233, 1877833, 1950457

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Example

42181 is a term because 42181 and 42187 are sexy primes while 42182-42186 each have 4 prime divisors (counting multiplicity).

Mathematica

Select[Range[2*10^6], AllTrue[{#, #+6}, PrimeQ]&&Length[Union[ PrimeOmega[ Range[ #+1, #+5]]]]==1&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 16 2015 *)

Prog

(Magma) f:=func<n|&+[p[2]: p in Factorization(n)]>; [p:p in PrimesUpTo(2000000)| IsPrime(p+6) and forall{k:k in [2..5]|f(p+k) eq f(p+1)} ]; // Marius A. Burtea, Dec 16 2019

Crossrefs

Cf. A023201, A046117.

Sequence in context: A302559 A232073 A278206 * A292069 A107440 A218055

Adjacent sequences: A094228 A094229 A094230 * A094232 A094233 A094234

Keyword

easy,nonn

Author

Jason Earls, May 29 2004

Status

approved