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A065397 Primes which have no representation p + k*(k+1) / 2, with p prime and k > 0: A000040-Complement of A065396. 5
2, 7, 61, 211 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..4.

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

CROSSREFS

Cf. A000040, A000217, A065377, A065396.

Sequence in context: A091687 A000892 A211875 * A255904 A046846 A111010

Adjacent sequences:  A065394 A065395 A065396 * A065398 A065399 A065400

KEYWORD

more,nonn

AUTHOR

Reinhard Zumkeller, Nov 05 2001

STATUS

approved

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Last modified February 27 03:03 EST 2020. Contains 332299 sequences. (Running on oeis4.)