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 A190359 Largest prime factor of the least number having exactly two odd prime factors that differ by 2^n. 0
 5, 7, 11, 19, 37, 67, 131, 263, 523, 1031, 2053, 4099, 8209, 16421, 32771, 65539, 131101, 262147, 524341, 1048583, 2097169, 4194371, 8388619, 16777259, 33554473, 67108961, 13417757, 268435459 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The least number having exactly two odd prime factors that differ by 2^n is  given by the sequence A190358. LINKS EXAMPLE a(5) = 37 because A190358(5) = 185 = 5 * 37 , and 37 is the largest prime divisor   such that 37 - 5 = 32 = 2^5. MAPLE with(numtheory):for m from 1 to 30 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, `, x[2]):else fi:od:od: CROSSREFS Cf. A190358. Sequence in context: A159080 A227770 A038881 * A045441 A128841 A057733 Adjacent sequences:  A190356 A190357 A190358 * A190360 A190361 A190362 KEYWORD nonn AUTHOR Michel Lagneau, May 09 2011 STATUS approved

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Last modified April 8 21:44 EDT 2020. Contains 333329 sequences. (Running on oeis4.)