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A224795 Smallest prime q such that 2n+1 = 2p - q^3 for some odd prime p, or 0 if no such prime exists. 2
7, 17, 3, 5, 3, 61, 7, 5, 3, 5, 11, 37, 0, 53, 3, 5, 3, 13, 7, 5, 7, 37, 3, 13, 7, 5, 3, 193, 3, 13, 19, 29, 3, 5, 11, 109, 19, 5, 3, 5, 131, 109, 11, 5, 3, 5, 3, 61, 23, 5, 7, 13, 3, 13, 7, 29, 3, 29, 3, 73, 7, 0, 331, 5, 3, 61, 7, 5, 3, 53, 59, 13, 11, 5, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See the conjecture and the comments in A224794, and the corresponding primes p.

LINKS

Michel Lagneau, Table of n, a(n) for n = 1..10000

EXAMPLE

a(4) = 5 because, for (p, q) = (67, 5),  2*4+1 = 9 = 2*67 - 5^3 = 134 - 125 = 9.

MAPLE

for n from 3 by 2 to 200 do:jj:=0:for j from 1 to 50000 while (jj=0) do:q:=ithprime(j):p:=(q^3+n)/2:if type(p, prime)=true  then jj:=1: printf(`%d, `, q):else fi:od:if jj=0 then printf(`%d, `, 0):else fi:od:

CROSSREFS

Cf. A224730, A185046, A224794.

Sequence in context: A107778 A122735 A094464 * A138449 A156680 A107804

Adjacent sequences:  A224792 A224793 A224794 * A224796 A224797 A224798

KEYWORD

nonn

AUTHOR

Michel Lagneau, Apr 18 2013

STATUS

approved

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Last modified March 30 15:42 EDT 2020. Contains 333127 sequences. (Running on oeis4.)