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A195352 Smallest prime p such that 2*n+1 = 2*p + q for some odd prime q. 5
2, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 3, 7, 2, 2, 3, 5, 2, 3, 2, 2, 3, 2, 3, 7, 2, 3, 7, 2, 2, 3, 5, 2, 3, 2, 2, 3, 5, 2, 3, 2, 3, 19, 2, 3, 7, 5, 2, 3, 2, 2, 3, 2, 2, 3, 2, 3, 7, 5, 11, 7, 11, 2, 3, 2, 3, 13, 2, 2, 3, 5, 5, 7, 2, 2, 3, 5, 2, 3, 7, 2, 3, 2, 3, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Related to Lemoine's conjecture, which states that all odd integers > 5 can be represented as 2*p+q, p, q primes.

REFERENCES

See A002091.

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 3..10000

Wikipedia, Lemoine's conjecture

EXAMPLE

a(3)=2 because 2*3+1=7=2*2+3; a(4)=2: 2*3+1=9=2*2+5; a(5)=2: 11=2*2+7; a(6)=3: 13=2*3+7.

CROSSREFS

Cf. A002091, A103506 (smallest q), A046927, A195353 (positions of records), A195354 (records), A103153 (prime p=2 excluded), A185091.

Sequence in context: A173883 A022922 A239141 * A103507 A219252 A290839

Adjacent sequences:  A195349 A195350 A195351 * A195353 A195354 A195355

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Sep 16 2011

STATUS

approved

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Last modified September 17 19:16 EDT 2019. Contains 327137 sequences. (Running on oeis4.)