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 A045939 Numbers n such that factorizations of n through n+2 have the same number of primes (including multiplicities). 12
 33, 85, 93, 121, 141, 170, 201, 213, 217, 244, 284, 301, 393, 428, 434, 445, 506, 602, 603, 604, 633, 637, 697, 841, 921, 962, 1041, 1074, 1083, 1084, 1130, 1137, 1244, 1261, 1274, 1309, 1345, 1401, 1412, 1430, 1434, 1448, 1490, 1532, 1556, 1586, 1604 (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 MATHEMATICA f[n_]:=Plus@@Last/@FactorInteger[n]; lst={}; lst={}; Do[If[f[n]==f[n+1]==f[n+2], AppendTo[lst, n]], {n, 0, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, May 12 2010 *) pd2Q[n_]:=PrimeOmega[n]==PrimeOmega[n+1]==PrimeOmega[n+2]; Select[Range[1700], pd2Q]  (* Harvey P. Dale, Apr 19 2011 *) PROG (PARI) is(n)=my(t=bigomega(n)); bigomega(n+1)==t && bigomega(n+2)==t \\ Charles R Greathouse IV, Sep 14 2015 (PARI) list(lim)=my(v=List(), a=1, b=1, c); forfactored(n=4, lim\1+2, c=bigomega(n); if(a==b&&a==c, listput(v, n[1]-2)); a=b; b=c); Vec(v) \\ Charles R Greathouse IV, May 07 2020 CROSSREFS A056809 is a subsequence. Cf. A006073. - Harvey P. Dale, Apr 19 2011 Subsequence of A045920. _Zak Seidov, Jul 02 2020 Sequence in context: A094846 A044171 A044552 * A056809 A073251 A005238 Adjacent sequences:  A045936 A045937 A045938 * A045940 A045941 A045942 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified January 23 20:39 EST 2021. Contains 340386 sequences. (Running on oeis4.)