

A279241


Let f(n) = 4*n^2 + 2*n + 41. The values f(n) are primes for all n in the range 20 to 19 (but not for n=21 or 20). The sequence lists this maximal run of primes in the order in which they appear.


0



1601, 1447, 1301, 1163, 1033, 911, 797, 691, 593, 503, 421, 347, 281, 223, 173, 131, 97, 71, 53, 43, 41, 47, 61, 83, 113, 151, 197, 251, 313, 383, 461, 547, 641, 743, 853, 971, 1097, 1231, 1373, 1523
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OFFSET

1,1


COMMENTS

This same list will also appear for 0<=x<=39 using the form 4x^2158x+1601.
The substitution 2n = m changes this quadratic form into Euler's famous quadratic form m^2+m+41 (see A005846). Concerning the conjectured extremal properties of these forms, one should note the comment from T. D. Noe in A005846. For another quadratic form similar to this one, see A145096.  N. J. A. Sloane, Dec 17 2016


LINKS



MAPLE

s1:=[]; f:=n>4*n^2+2*n+41;
for n from 20 to 19 do if isprime(abs(f(n))) then s1:=[op(s1), abs(f(n))]; fi; od:
s1; # From N. J. A. Sloane, Dec 17 2016. This does nothing more than produce the primes mentioned in the definition


CROSSREFS



KEYWORD

fini,nonn


AUTHOR



EXTENSIONS



STATUS

approved



