

A335592


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


4



188, 678, 1568, 2798, 2768, 3928, 9328, 9418, 16918, 12418, 19428, 19578, 16898, 34698, 28028, 30988, 35878, 58528, 53908, 52318, 54938, 37308, 53098, 49888, 49758, 68688, 65738, 74328, 96558, 100098, 95548, 121898, 119108, 117438, 104078, 140698, 156588, 143168, 222888, 226608, 196448, 160448
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OFFSET

1,1


COMMENTS

All terms == 8 (mod 10).
Are there negative terms? The first 10^7 are positive.


LINKS



EXAMPLE

The first primes ending in 1,3,7,9 are 11,3,7,19, so a(1) = 11*19  3*7 = 188.
The second primes ending in 1,3,7,9 are 31,13,17,29, so a(2) = 31*29  13*17 = 678.
The third primes ending in 1,3,7,9 are 41,23,37,59, so a(3) = 41*59  23*37 = 1568.


MAPLE

R:= NULL:
L:= [9, 7, 3, 1]:
for k from 1 to 100 do
for i from 1 to 4 do
for x from L[i]+10 by 10 do until isprime(x);
L[i]:= x;
od;
R:= R, L[1]*L[4]L[2]*L[3];
od:
R;


CROSSREFS



KEYWORD



AUTHOR



STATUS

approved



