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A042978
Stern primes: primes not of the form p + 2b^2 for p prime and b > 0.
6
2, 3, 17, 137, 227, 977, 1187, 1493
OFFSET
1,1
COMMENTS
No others < 1299709. Are there any others?
Related to a conjecture of Goldbach.
The next term of the sequence, if it exists, is larger than 10^9; see A060003. - M. F. Hasler, Nov 16 2007
The next term, if it exists, is larger than 2*10^13. - Benjamin Chaffin, Mar 28 2008
Does not equal A000040(k) + A001105(j) for all k and j > 0. - Robert G. Wilson v, Sep 07 2012
Named after the German mathematician Moritz Abraham Stern (1807-1894). - Amiram Eldar, Feb 01 2026
REFERENCES
Albert H. Beiler, Recreations in the theory of numbers, Dover, New York, 2nd ed., 1966. See p. 226.
Jean-Marie De Koninck, Ces nombres qui nous fascinent, Entry 137, p. 46, Ellipses, Paris, 2008.
L. E. Dickson, History of the Theory of Numbers, Vol. 1, Chelsea, N.Y., 1952, page 424.
LINKS
Ernest G. Hibbs, Component Interactions of the Prime Numbers, Ph.D. Thesis, Capitol Technology Univ. (2022), see p. 33.
Laurent Hodges, A lesser-known Goldbach conjecture, Math. Mag., Vol. 66, No. 1 (1993), 45-47.
Moritz A. Stern, Sur un assertion de Goldbach relative aux nombres impairs, Nouvelles Annales Math., Vol. 15 (1856), pp. 23-24.
Wikipedia, Stern prime.
MAPLE
N:= 10^6: # to check primes up to N
P:= select(isprime, {2, seq(i, i=3..N, 2)}):
S:= {seq(2*b^2, b=1..floor(sqrt(N/2)))}:
P minus {seq(seq(p+s, p=P), s=S)}; # Robert Israel, Jan 19 2016
MATHEMATICA
fQ[n_] := Block[{k = Floor[ Sqrt[ n/2]]}, While[k > 0 && !PrimeQ[n - 2*k^2], k--]; k == 0]; Select[ Prime[Range[238]], fQ] (* Robert G. Wilson v, Sep 07 2012 *)
PROG
(PARI) forprime( n=1, default(primelimit), for(s=1, sqrtint(n\2), if(isprime(n-2*s^2), next(2))); print(n)) \\ M. F. Hasler, Nov 16 2007
(PARI) forprime(p=2, 4e9, forstep(k=sqrt(p\2), 1, -1, if(isprime(p-2*k^2), next(2))); print1(p", ")) \\ Charles R Greathouse IV, Aug 04 2011
CROSSREFS
Apart from the first term, a subsequence of A060003.
Sequence in context: A135726 A259535 A328340 * A089675 A388062 A041383
KEYWORD
nonn,more
AUTHOR
STATUS
approved