A089719 Pseudofactor sets of primes ending in 1: 9 greater than 3.

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

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

Table of n, a(n) for n=1..47.

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: A348558 A088555 A040178 * A340444 A109550 A040991

Adjacent sequences: A089716 A089717 A089718 * A089720 A089721 A089722

Keyword

nonn,uned

Author

Roger L. Bagula, Jan 06 2004

Status

approved