A065397 Primes which have no representation p + k*(k+1) / 2, with p prime and k > 0: A000040-Complement of A065396.

2, 7, 61, 211

Offset: 1

Author

Reinhard Zumkeller, Nov 05 2001

Keywords

• more
• nonn

Comments

Finite? (Checked up to A000040(100000) = 1299709.)

Next term > 7000000. - R. J. Mathar, Apr 23 2006

No other terms less than 2*10^9. - T. D. Noe, Mar 26 2008

Crossrefs

Cf. A000040, A000217, A065377, A065396.

Programs

Maple

for n from 1 to 7000000 do if isprime(n) = true then foundp := false ; for k from 1 to n do if isprime(n-k*(k+1)/2) = true then foundp := true ; break ; elif n-k*(k+1)/2 < 2 then break ; fi ; od ; if foundp = false then print(n) ; fi ; fi ; od : # R. J. Mathar, Apr 23 2006