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Search: id:A113302
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| A113302 |
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Number of k such that prime(n) divides T(k), the central trinomial coefficient A002426(k), with 0<k<prime(n). |
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+0
5
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| 0, 1, 0, 1, 0, 0, 2, 2, 0, 0, 0, 0, 4, 2, 3, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 2, 2, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 3, 4, 0, 2, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 2, 0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 3, 0, 0, 4, 2, 2, 4, 0, 0, 3, 2, 0, 2, 0, 0, 2, 0, 0, 0, 0, 6, 2, 2, 0, 0, 2, 0, 4, 2, 0
(list; graph; listen)
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OFFSET
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1,7
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COMMENT
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For primes less than 10^6, a(n) <= 10. Is 10 the largest possible value? When a(n)=0, prime(n) is in A113305. When a(n)>0, prime(n) is in A113304.
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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}]]; Table[p=Prime[i]; cnt=0; Do[If[Mod[t[[j]], p]==0, cnt++ ], {j, p}]; cnt, {i, PrimePi[nn]}]
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CROSSREFS
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Cf. A113303 (least k such that prime(n) divides T(k)).
Sequence in context: A035447 A037863 A163536 this_sequence A049800 A131018 A035395
Adjacent sequences: A113299 A113300 A113301 this_sequence A113303 A113304 A113305
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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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