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A214197
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Primes of the "second kind".
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2
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2, 3, 5, 7, 11, 19, 23, 47, 59, 61, 71, 101, 113, 223, 487, 661, 719, 811, 947, 1327, 1621, 2039, 2161, 2377, 2381, 2699, 2957, 3011, 3607, 3727, 4093, 4549, 4649, 5939, 6473, 8363, 9601
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OFFSET
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1,1
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COMMENTS
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See Sun 2012 for precise definition. This term is overworked, and it would be good to include a more precise definition here.
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LINKS
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MATHEMATICA
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primorial[n_] := primorial[n] = Product[Prime[i], {i, 1, n}];
p[0] = 1; p[n_] := p[n] = Module[{m, i, j, ddvs}, For[m = 2, True, m++, ddvs = False; For[i = 1, i <= n - 1, i++, For[j = i + 1, j <= n, j++, If[Mod[primorial[j] + primorial[i], m] == 0, ddvs = True; Break[]]]; If[ddvs, Break[]]]; If[ddvs == False, Return[m]]]];
A214197 = Reap[n = k = 1; While[n <= 400, If[p[n] != p[n - 1], a[k] = p[n]; Print[n, " a(", k, ") = ", a[k]]; Sow[a[k]]; k++]; n++]][[2, 1]] (* Jean-François Alcover, Jan 20 2018, after R. J. Mathar *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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