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 A224693 Smallest prime p such that p > gpf(p+1) > gpf(p+2) > ... > gpf(p+n) where gpf(m) is the greatest prime factor of m. 0
 3, 13, 13, 491, 2011, 12721, 12721, 109453, 586951, 173912393, 785211341, 4044619541, 315400191511, 315400191511 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) >= A100385(n+1). - Zak Seidov, Apr 17 2013 LINKS EXAMPLE a(4) = 491 because 491 > 41 > 29 > 19 > 11 where: 492 = 2^2*3*41; 493 = 17*29; 494 = 2*13*19; 495 = 3^2*5*11. MAPLE with(numtheory): for n from 1 to 20 do:    ii:=0:         for k from 1 to 10^7 while(ii=0) do:         p:=ithprime(k): it:=0:             for m from 1 to n do:                x0:=factorset(p+m-1):n0:=nops(x0): x1:=factorset(p+m):n1:=nops(x1):                if x0[n0] > x1[n1]                then                it:=it+1:               else               fi:           od:              if it=n              then              printf ( "%d %d \n", n, p):ii:=1:              else              fi:         od:     od: CROSSREFS Cf. A006530, A100385. Sequence in context: A076747 A198452 A286190 * A043055 A101235 A230508 Adjacent sequences:  A224690 A224691 A224692 * A224694 A224695 A224696 KEYWORD nonn,hard,more AUTHOR Michel Lagneau, Apr 15 2013 EXTENSIONS a(10)-a(12) from Zak Seidov, Apr 17 2013 a(13)-a(14) from Donovan Johnson, Apr 26 2013 STATUS approved

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Last modified January 22 12:55 EST 2022. Contains 350481 sequences. (Running on oeis4.)