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A145193 Omega(6n-1) + Omega(6n+1). 3
2, 2, 2, 3, 2, 3, 2, 3, 3, 2, 3, 2, 3, 3, 3, 3, 2, 2, 3, 4, 4, 3, 2, 4, 2, 3, 3, 3, 4, 2, 4, 2, 2, 4, 3, 4, 3, 2, 3, 2, 5, 3, 3, 3, 2, 4, 2, 4, 3, 4, 3, 2, 3, 5, 3, 3, 5, 2, 3, 3, 3, 3, 3, 4, 3, 3, 3, 3, 4, 2, 5, 2, 3, 3, 3, 4, 2, 3, 5, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A001222(6n-1) + A001222(6n+1). - Michel Marcus, Sep 04 2013

EXAMPLE

For n=1, Omega(6n-1) + Omega(6n+1) = Omega(5) + Omega(7) = 1+1 = 2, so a(1)=2.

MATHEMATICA

For[x=6, x<601, x+=6, S=0; T=0; For[k=1, k< Length[FactorInteger[x-1]]+1, k++, S+= FactorInteger[x-1][[k]][[2]]]; For[m=1, m<Length[FactorInteger[x+1]]+1, m++, T+= FactorInteger[x+1][[m]][[2]]]; Print[x/6, " ", S+T]]

Table[Total[PrimeOmega/@(6n+{1, -1})], {n, 60}] (* Harvey P. Dale, May 22 2013 *)

PROG

(PARI) a(n) = bigomega(6*n-1) + bigomega(6*n+1); \\ Michel Marcus, Sep 04 2013

CROSSREFS

Cf. A145194.

Sequence in context: A318490 A071215 A164024 * A292585 A175872 A143117

Adjacent sequences:  A145190 A145191 A145192 * A145194 A145195 A145196

KEYWORD

nonn,easy

AUTHOR

Arran Fernandez, Oct 03 2008

EXTENSIONS

More terms from Michel Marcus, Sep 04 2013

STATUS

approved

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Last modified March 2 19:18 EST 2021. Contains 341756 sequences. (Running on oeis4.)