STATUS
editing
approved
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Revision History for A124057
(Bold, blue-underlined text is an addition; faded, red-underlined text is aShowing entries 1-10 | older changes
Numbers n such that n, n+1, n+2 and n+3 are products of exactly 3 primes.
(history; published version)
(history; published version)
PROG
(PARI) is(n)=if(!isprime((n+3)\4), return(0)); for(k=n, n+3, if(bigomega(k)!=3, return(0))); 1 \\ Charles R Greathouse IV, Feb 05 2017
(PARI) list(lim)=my(v=List(), u=v, t); forprime(p=2, lim\4, forprime(q=2, min(lim\(2*p), p), t=p*q; forprime(r=2, min(lim\t, q), listput(u, t*r)))); u=Set(u); for(i=4, #u, if(u[i]-u[i-3]==3, listput(v, u[i-3]))); Vec(v) \\ Charles R Greathouse IV, Feb 05 2017
STATUS
approved
editing
STATUS
reviewed
approved
STATUS
proposed
reviewed
STATUS
editing
proposed
MATHEMATICA
okQ[{a_, b_, c_, d_}]:=Union[{a, b, c, d}]=={3}; Flatten[Position[Partition[ PrimeOmega[ Range[11000]], 4, 1], _?(okQ)]] (* Harvey P. Dale, Sep 23 2012 *)
COMMENTS
A subset of A045940. - _Zak Seidov, _, Nov 05 2006
MAPLE
with(numtheory): a:=proc(n) if bigomega(n)=3 and bigomega(n+1)=3 and bigomega(n+2)=3 and bigomega(n+3)=3 then n else fi end: seq(a(n), n=1..15000); - _# _Emeric Deutsch_, Nov 07 2006
EXTENSIONS
More terms from _Zak Seidov, _, Nov 05 2006
STATUS
proposed
editing
STATUS
editing
proposed
COMMENTS
A subset of A045940. - Zak Seidov, Nov 05 2006 - Zak Seidov, Nov 05 2006
STATUS
approved
editing
STATUS
editing
approved