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 A190663 Largest prime factor of the least semiprime whose prime factors differ by 2*n! 1
 5, 7, 17, 53, 251, 1447, 10091, 80651, 725789, 7257629, 79833613, 958003271, 12454041629, 174356582419, 2615348736019, 41845579776037, 711374856192023, 12804747411456023 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(5) = 251 because A190662(5) = 2761 = 11 * 251 , and 251 is the largest prime   divisor such that 251 - 11 = 240 = 2*120 = 2*5! MAPLE with(numtheory):for m from 1 to 18 do: k:=2*m!:id:=0:for n from 1 to 900000000   while(id=0) do: x:=factorset(n):n1:=nops(x):n2:=bigomega(n):if n1=2 and n2=2   and x[2]=x[1]+k then id:=1:printf ( "%d %d \n", m, x[2]):else fi:od:od: CROSSREFS Cf. A190662. Sequence in context: A248085 A079604 A101580 * A123195 A248480 A243844 Adjacent sequences:  A190660 A190661 A190662 * A190664 A190665 A190666 KEYWORD nonn AUTHOR Michel Lagneau, May 16 2011 STATUS approved

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Last modified January 19 20:41 EST 2020. Contains 331066 sequences. (Running on oeis4.)