A224730 Smallest prime q such that 2n+1 = p^3 - 2q for some odd prime p, or 0 if no such prime exists.

61, 11, 59, 167, 1093, 7, 1091, 5, 53, 3, 2, 653, 0, 157, 47, 3413, 25309, 647, 43, 151, 41, 149, 25303, 641, 37, 14869, 74411, 14867, 1069, 6053, 31, 139, 29, 137, 1063, 6047, 1061, 3391, 23, 131, 37309189, 51869, 19, 127, 17, 619, 1051, 617, 13, 39703, 11

Offset: 1

Author

Michel Lagneau, Apr 17 2013

Keywords

• nonn

Comments

See the conjecture and the comments in A185046, and the corresponding primes p.

Examples

			a(4) = 167 because, for (p, q) = (7, 167),  9 = 7^3 - 2*167 = 343 - 334 = 9.
		

Links

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

Crossrefs

Cf. A185046.

Programs

Maple

for n from 3 by 2 to 200 do:
jj:=0:
  for j from 1 to 10000 while (jj=0) do:
   p:=ithprime(j):q:=(p^3-n)/2:
    if q> 0 and type(q, prime)=true
    then
    jj:=1:printf(`%d, `, q):
   else
   fi:
  od:
  if jj=0 then
  printf(`%d, `, 0):
  else
  fi:
od: