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Search: id:A133661
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| A133661 |
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No sum of 2 or more terms equals a prime, terms alternate parity and there are no primes in the list. |
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+0
3
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| 1, 8, 25, 86, 209, 472, 25719, 238350, 41931245, 14426603100
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(10) > 263811880. - Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 01 2008
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EXAMPLE
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25 is a term, because 25 is odd (previous term was even), 25 is composite, and 25+1, 25+8 and 25+8+1 are all composite.
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MATHEMATICA
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(* first do *) Needs["Combinatorica`"] (* then *) lst = {1, 8}; g[k_] := Block[{j = 1, l = 2^Length@lst}, While[j < l && !PrimeQ[Plus @@ NthSubset[j, lst] + k], j++ ]; If[j == l, False, True]]; f[n_] := Block[{k = lst[[ -1]] + 1}, While[PrimeQ@k || g[k] == True, k++; k++ ]; AppendTo[lst, k]; k]; Do[ Print@ f@ n, {n, 10}] - Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 01 2008
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CROSSREFS
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Cf. A052349, A133660.
Adjacent sequences: A133658 A133659 A133660 this_sequence A133662 A133663 A133664
Sequence in context: A035073 A041120 A042637 this_sequence A139026 A135942 A068315
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KEYWORD
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more,nonn
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AUTHOR
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Randy L. Ekl (Randy.Ekl(AT)Motorola.com), Dec 28 2007
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EXTENSIONS
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a(9) from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 01 2008
a(10) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 15 2008
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