

A160440


Smaller member of a pair (p,q) of cousin primes such that p and q are in different centuries.


9



97, 397, 499, 1297, 1597, 1999, 2797, 3697, 4999, 6199, 6997, 7699, 9199, 10099, 10597, 12097, 13099, 16699, 18397, 20899, 21397, 21499, 21799, 23197, 23599, 25999, 26497, 27697, 27799, 27997, 32299, 32797, 33199, 34297, 35797, 38197, 38299, 39499, 42697
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OFFSET

1,1


COMMENTS

Sequence is probably infinite.
It appears that every integer occurs as the difference round((a(n+1)a(n))/100); all numbers 1..298 occur as these differences for a(n) < 1000000000.  Hartmut F. W. Hoft, May 18 2017


LINKS

Table of n, a(n) for n=1..39.


FORMULA

{A023200(n): [A023200(n)/100] <> [A046132(n)/100]}, where [..]=floor(..).


EXAMPLE

Cousin primes 1597 and 1601 are in successive (that is 16th and 17th) centuries.


MATHEMATICA

a160440[n_] := Map[Last, Select[Map[{NextPrime[#, 1], NextPrime[#, 1]}&, Range[100, n, 100]], First[#]Last[#]==4&]]
a160440[43000] (* data *) (* Hartmut F. W. Hoft, May 18 2017 *)


CROSSREFS

Cf. A046132, A160370
Sequence in context: A031927 A174338 A050666 * A107213 A157331 A142834
Adjacent sequences: A160437 A160438 A160439 * A160441 A160442 A160443


KEYWORD

nonn


AUTHOR

Ki Punches, May 13 2009


EXTENSIONS

Edited by R. J. Mathar, May 14 2009


STATUS

approved



