login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A335592 a(n) is the determinant of the 2 X 2 matrix whose entries (listed by rows) are the n-th prime ending in 1, 3, 7, 9 respectively. 4

%I

%S 188,678,1568,2798,2768,3928,9328,9418,16918,12418,19428,19578,16898,

%T 34698,28028,30988,35878,58528,53908,52318,54938,37308,53098,49888,

%U 49758,68688,65738,74328,96558,100098,95548,121898,119108,117438,104078,140698,156588,143168,222888,226608,196448,160448

%N a(n) is the determinant of the 2 X 2 matrix whose entries (listed by rows) are the n-th prime ending in 1, 3, 7, 9 respectively.

%C All terms == 8 (mod 10).

%C Are there negative terms? The first 10^7 are positive.

%H Robert Israel, <a href="/A335592/b335592.txt">Table of n, a(n) for n = 1..10000</a>

%e The first primes ending in 1,3,7,9 are 11,3,7,19, so a(1) = 11*19 - 3*7 = 188.

%e The second primes ending in 1,3,7,9 are 31,13,17,29, so a(2) = 31*29 - 13*17 = 678.

%e The third primes ending in 1,3,7,9 are 41,23,37,59, so a(3) = 41*59 - 23*37 = 1568.

%p R:= NULL:

%p L:= [-9,-7,-3,-1]:

%p for k from 1 to 100 do

%p for i from 1 to 4 do

%p for x from L[i]+10 by 10 do until isprime(x);

%p L[i]:= x;

%p od;

%p R:= R, L[1]*L[4]-L[2]*L[3];

%p od:

%p R;

%Y Cf. A335581, A335593, A336738.

%K nonn,base,look

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 27 2021

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 22 07:06 EDT 2021. Contains 348160 sequences. (Running on oeis4.)