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Echoes of ONU Research - Greatest Prime Factor Sequences

There are 5 entries devoted to our "greatest prime factor sequences" in The Online Encyclopedia of Integer Sequences (OEIS). The entries have been communicated by Neil Sloane, Technology Leader at AT&T Research Labs.

http://oeis.org/A006530  Gpf(n): greatest prime dividing n (with a(1)=1).
http://oeis.org/A175723  a(1)=a(2)=1; thereafter a(n) = gpf(a(n-1)+a(n-2))
http://oeis.org/A177904 a(1)=a(2)=a(3)=1; thereafter a(n) = gpf(a(n-1)+a(n-2)+a(n-3))
http://oeis.org/A177923  a(1)=19, a(2)=13, a(3)=37; thereafter a(n)=gpf(a(n-1)+a(n-2)+a(n-3))
http://oeis.org/A178174  a(1)=a(2)=a(3)=a(4)=1; thereafter a(n)=gpf(a(n-1)+a(n-2)+a(n-3)+a(n-4))

The sequences introduced in the paper The Greatest Prime Factor and Recurrent Sequences (Fibonacci Quarterly 48, no. 4, 358-362) by Greg Back (ONU '10) and Dr. Mihai Caragiu (Professor of Mathematics) have been one of the topics discussed in Rutgers University's Experimental Mathematics Seminar