HSNVA

Cho 1 bang co kich thuoc 1998.2000 (1998 hang va 2000 cot)
Goi (m,n) la o nam o hang m va cot n.
Voi 1<=p,q<=1993, to mau cac o vuong cua bang theo nguyen tac: lan 1 to mau 5 o (p,q);(p+1,q+1);...;(p+4,q+4). Tu lan thu 2 tro di, moi lan to 5 o chua co mau len tiep trong cung 1 hang hoac 1 cot. Hoi co the to het dc ko???

Cho day so 1,2,3,...,2005,2006
Thay doi vi tri cac so theo nguyen tac: moi lan lay ra 4 so bat ki roi xep theo thu tu nguoc lai. Co the xep ve vi tri:
2006,2005,...,3,2,1 dc ko?????????

Cho Q(x)= x^{3) + 19x^{2}+ 99x + a voi a Z
CMR p P, p 5 thi trong day gom p so nguyen
Q(0), Q(1), ... , Q(p-1) khong the co nhieu hon 3 so p

Tim tat ca cac bo 3 so a, b, c nguyen duong sao cho:
a^{2} + 1, b^{2} +1 la so nguyen to va (a^{2} + 1)(b^{2} +1) = c^{2} +1

Biet P1<P2<P3<...
Voi P1, P2, P3,... la cac so nguyen to dau tien

1-CMR: Neu n>12 thi Pn>2n
2-CMR Ke tu luc nao do tro di chua biet thi Pn>4n