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Search: id:A113305
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| A113305 |
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Primes that do not divide any central trinomial coefficient, A002426. |
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+0
4
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| 2, 5, 11, 13, 23, 29, 31, 37, 53, 59, 61, 67, 71, 79, 83, 89, 97, 101, 103, 127, 137, 139, 149, 151, 157, 163, 167, 181, 197, 211, 223, 227, 229, 239, 241, 251, 257, 263, 271, 313, 317, 331, 337, 349, 353, 359, 367, 379, 389, 397, 431, 433, 449, 461, 463, 479
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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For primes less than 10^6, the density of these primes is near 0.6075.
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MATHEMATICA
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nn=1000; a=b=1; t=Join[{1}, Table[c=((2n-1)b+3(n-1)a)/n; a=b; b=c; c, {n, 2, nn}]]; pLst={}; Do[p=Prime[n]; k=1; While[k<p && Mod[t[[k]], p]>0, k++ ]; If[k==p, AppendTo[pLst, p]], {n, PrimePi[nn]}]; pLst
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CROSSREFS
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Cf. A113302 (number of k for which prime(n) divides T(k)), A113303 (least k such that prime(n) divides T(k)).
Sequence in context: A105961 A045361 A086081 this_sequence A095078 A062572 A106283
Adjacent sequences: A113302 A113303 A113304 this_sequence A113306 A113307 A113308
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), Oct 24 2005
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