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A089654 Table T(n,k), read by rows, related to a conjecture of P. Erdos (see A039669). 0
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; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..64.

P. Erdős, On integers of the form 2^k + p and some related questions, Summa Bras. Math., 2 (1950), 113-123.

FORMULA

T(n, k) = 2*n+1-2^k, if T(n, k)>0.

CROSSREFS

Cf. A039669.

Sequence in context: A136655 A060819 A318661 * A233526 A097062 A324894

Adjacent sequences:  A089651 A089652 A089653 * A089655 A089656 A089657

KEYWORD

easy,nonn,tabf

AUTHOR

Philippe Deléham, Jan 04 2004

STATUS

approved

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Last modified May 25 17:53 EDT 2020. Contains 334595 sequences. (Running on oeis4.)