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A236019
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Smallest number having at least n partitions that contain at least n primes.
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2
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0, 2, 5, 8, 10, 13, 15, 17, 20, 22, 24, 26, 28, 31, 33, 35, 37, 39, 41, 43, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130
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OFFSET
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0,2
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LINKS
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EXAMPLE
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a(4) = 10: [2,2,2,2,1,1], [2,2,2,2,2], [3,2,2,2,1], [3,3,2,2].
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MAPLE
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b:= proc(n, i, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
`if`(i<1, 0, b(n, i-1, t) +`if`(i>n, 0,
b(n-i, i, t -`if`(t>0 and isprime(i), 1, 0)))))
end:
a:= proc(n) option remember; local k;
for k from a(n-1) while b(k, k, n)<n do od; k
end: a(0):=0:
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MATHEMATICA
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$RecursionLimit = 1000; b[n_, i_, t_] := b[n, i, t] = If[n == 0, If[t == 0, 1, 0], If[i<1, 0, b[n, i-1, t] + If[i>n, 0, b[n-i, i, t - If[t>0 && PrimeQ[i], 1, 0]]]]]; a[n_] := a[n] = Module[{k}, For[k = a[n-1], b[k, k, n] < n, k++]; k]; a[0] = 0; Table[a[n], {n, 0, 61}] (* Jean-François Alcover, Jan 27 2014, after Alois P. Heinz *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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