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

1,1

Comments

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

Links

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

Example

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

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:

Crossrefs

Cf. A185046.

Sequence in context: A077331 A106426 A106416 * A248143 A012860 A002108

Adjacent sequences: A224727 A224728 A224729 * A224731 A224732 A224733

Keyword

nonn

Author

Michel Lagneau, Apr 17 2013

Status

approved