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 A089719 Pseudofactor sets of primes ending in 1: 9 greater than 3. 0
 31, 41, 61, 71, 131, 151, 211, 241, 251, 311, 331, 401, 421, 431, 491, 521, 571, 601, 661, 691, 701, 751, 761, 881, 941, 971, 1021, 1031, 1051, 1061, 1151, 1201, 1231, 1291, 1301, 1321, 1381, 1471, 1481, 1511, 1571, 1601, 1741, 1831, 1861, 1871, 1931 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS These pseudofactors although not unique sets as their domains seem to overlap form twelve subsets of primes based on the first digit set {1,3,7,9} when {2,5} are taken away from the prime set. I'm entering the four {1}'s sets. There exist {3}'s, {7}'s and {9}'s sets of these same four types. LINKS FORMULA a[n]=Primes ending in one b(m) = if Mod[a[[n]]/9, 10]>3 then a[n] MATHEMATICA digits=4*200 a=Delete[Union[Table[If[Mod[Prime[n], 10]==1, Prime[n], 0], {n, 1, digits}]], 1] d2=Dimensions[a][[1]] a9g3=Delete[Union[Table[If[Mod[a[[n]]/9, 10]>3, a[[n]], 0], {n, 1, d2}]], 1] CROSSREFS Sequence in context: A040969 A088555 A040178 * A109550 A040991 A089721 Adjacent sequences:  A089716 A089717 A089718 * A089720 A089721 A089722 KEYWORD nonn,uned AUTHOR Roger L. Bagula, Jan 06 2004 STATUS approved

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Last modified June 5 03:12 EDT 2020. Contains 334828 sequences. (Running on oeis4.)