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 A215081 Smallest number k such that the difference between the greatest prime divisor and the smallest prime divisor of k equals n,  or 0 if there is no such k. 0
 2, 6, 15, 10, 21, 14, 55, 0, 33, 22, 39, 26, 85, 0, 51, 34, 57, 38, 115, 0, 69, 46, 203, 0, 145, 0, 87, 58, 93, 62, 259, 0, 185, 0, 111, 74, 205, 0, 123, 82, 129, 86, 235, 0, 141, 94, 371, 0, 265, 0, 159, 106, 413, 0, 295, 0, 177, 118, 183, 122, 469, 0, 335, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(A007921(n)) = 0 where A007921(n) are the numbers that are not the difference of two primes. LINKS EXAMPLE a(2) = 15 because 15 = 3*5 and 5 - 3 = 2. MAPLE with(numtheory):for n from 0 to 65 do:ii:=0:for k from 2 to 10000 while(ii=0) do:x:=factorset(k):n1:=nops(x):d:=x[n1] - x[1]:if d=n then ii:=1: printf("%a, ", k):else fi:od:if ii=0 then printf("%a, ", 0):else fi:od: CROSSREFS Cf. A007921. Sequence in context: A130642 A133933 A297574 * A337737 A119416 A134891 Adjacent sequences:  A215078 A215079 A215080 * A215082 A215083 A215084 KEYWORD nonn AUTHOR Michel Lagneau, Aug 02 2012 STATUS approved

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Last modified November 30 05:11 EST 2021. Contains 349418 sequences. (Running on oeis4.)