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Search: id:A089654
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| A089654 |
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Table T(n,k), read by rows, related to a conjecture of P. Erdos (see A039669). |
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| 1, 3, 1, 5, 3, 7, 5, 1, 9, 7, 3, 11, 9, 5, 13, 11, 7, 15, 13, 9, 1, 17, 15, 11, 3, 19, 17, 13, 5, 21, 19, 15, 7, 23, 21, 17, 9, 25, 23, 19, 11, 27, 25, 21, 13, 29, 27, 23, 15, 31, 29, 25, 17, 1, 33, 31, 27, 19, 3, 35, 33, 29, 21, 5
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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row n=1 : 1
row n=2 : 3, 1
row n=3 : 5, 3
row n=4 : 7, 5, 1
row n=5 : 9, 7, 3
row n=6 : 11, 9, 5
row n=7 : 13, 11, 7
row n=8 : 15, 13, 9, 1
row n=9 : 17, 15, 11, 3
P. Erdos conjectures that T(n,k) are all primes for n = 3, 7, 10, 22, 37, 52 and these are the only values of n with property . The conjecture has been verified for n up to 2^77. example : n=10; 19, 17, 13, 5 are all primes.
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REFERENCES
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P. Erdos, On integers of the form 2^k + p and some related questions, Summa Bras.Math ., 2(1950), 113-123.
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FORMULA
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T(n, k) = 2*n+1-2^k, if T(n, k)>0.
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CROSSREFS
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Cf. A039669.
Sequence in context: A081432 A136655 A060819 this_sequence A097062 A077881 A129095
Adjacent sequences: A089651 A089652 A089653 this_sequence A089655 A089656 A089657
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KEYWORD
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easy,nonn,tabf
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AUTHOR
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DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Jan 04 2004
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