A224795 Smallest prime q such that 2n+1 = 2p - q^3 for some odd prime p, or 0 if no such prime exists.
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
Offset: 1
Keywords
Examples
a(4) = 5 because, for (p, q) = (67, 5), 2*4+1 = 9 = 2*67 - 5^3 = 134 - 125 = 9.
Links
- Michel Lagneau, Table of n, a(n) for n = 1..10000
Programs
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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:
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