AUTHOR
_Robert G. Wilson v (rgwv(AT)rgwv.com), _, Mar 20 2003
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Revision History for A081428
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LINKS
R. J. Mathar, <a href="/A081428/b081428.txt">Table of n, a(n) for n = 1..6505</a>
KEYWORD
nonn,new
nonn
LINKS
R. J. Mathar, <a href="http://www.research.att.com/~njas/sequences/b081428.txt">Table of n, a(n) for n = 1..6505</a>
KEYWORD
nonn,new
nonn
LINKS
Richard R. J. Mathar, <a href="http://www.research.att.com/~njas/sequences/b081428.txt">Table of n, a(n) for n = 1..6505</a>
KEYWORD
nonn,new
nonn
LINKS
Richard Mathar, <a href="http://www.research.att.com/~njas/sequences/b081428.txt">Table of n, a(n) for n = 1..6505</a>
KEYWORD
nonn,new
nonn
NAME
Class 9- primes.
DATA
34549, 86371, 103613, 120919, 138059, 149519, 172583, 172741, 224563, 276293, 282059, 282143, 293659, 299417, 316691, 352399, 368513, 379903, 397303, 403061, 414577, 451499, 483179, 486527, 489431, 500947, 506537, 517747, 518047, 541799
OFFSET
1,1
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, A18.
MATHEMATICA
PrimeFactors[n_Integer] := Flatten[Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] - 1]]; ClassMinusNbr[n_] := Length[NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[50000], ClassMinusNbr[ Prime[ # ]] == 9 &]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 20 2003
STATUS
approved