A089724 Numbers p satisfying the following conditions: p is a prime of form 10k+9 and the function f[p,7,10] applied to p is not greater than 5, where f[p,7,10]=10*fractionalpart[n/70]=1*.((n/70)-Floor[n/70]).
19, 29, 79, 89, 149, 229, 239, 359, 379, 439, 449, 499, 509, 569, 659, 709, 719, 859, 919, 929, 1009, 1069, 1129, 1279, 1289, 1409, 1429, 1489, 1499, 1549, 1559, 1619, 1699, 1709, 1759, 1979, 2039, 2129, 2179, 2269, 2339, 2389, 2399, 2459, 2539, 2549
Offset: 1
Keywords
Crossrefs
Cf. A034433.
Programs
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Mathematica
f[x_, d_, m_] := Mod[x/d, m]; (* or alternatively *) f[x_, d_, m_] := m*(x/(d*m)-Floor[x/(d*m)]); Do[If[PrimeQ[n]&&Equal[Mod[n, 10], 9]&&!Greater[f[n, 7, 10], 5], Print[n]], {n, 1, 1000}]
Extensions
Edited by Labos Elemer, Jan 24 2004