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Problems


IDDescription / TitleSolved By
151
Paper sheets of standard sizes: an expected-value problem.
2165
152
Writing 1/2 as a sum of inverse squares
1096
153
Investigating Gaussian Integers
1049
154
Exploring Pascal's pyramid.
1106
155
Counting Capacitor Circuits.
1485
156
Counting Digits
997
157
Solving the diophantine equation 1/a+1/b= p/10n
1122
158
Exploring strings for which only one character comes lexicographically after its neighbour to the left.
1568
159
Digital root sums of factorisations.
1401
160
Factorial trailing digits
1387
161
Triominoes
896
162
Hexadecimal numbers
2487
163
Cross-hatched triangles
830
164
Numbers for which no three consecutive digits have a sum greater than a given value.
2572
165
Intersections
1121
166
Criss Cross
1786
167
Investigating Ulam sequences
754
168
Number Rotations
1168
169
Exploring the number of different ways a number can be expressed as a sum of powers of 2.
1915
170
Find the largest 0 to 9 pandigital that can be formed by concatenating products.
863
171
Finding numbers for which the sum of the squares of the digits is a square.
1088
172
Investigating numbers with few repeated digits.
1668
173
Using up to one million tiles how many different "hollow" square laminae can be formed?
4125
174
Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements.
2761
175
Fractions involving the number of different ways a number can be expressed as a sum of powers of 2.
847
176
Rectangular triangles that share a cathetus.
893
177
Integer angled Quadrilaterals.
596
178
Step Numbers
1541
179
Consecutive positive divisors
5208
180
Rational zeros of a function of three variables.
729
181
Investigating in how many ways objects of two different colours can be grouped.
846
182
RSA encryption
1165
183
Maximum product of parts
2305
184
Triangles containing the origin.
715
185
Number Mind
1409
186
Connectedness of a network.
1252
187
Semiprimes
5092
188
The hyperexponentiation of a number
3124
189
Tri-colouring a triangular grid
900
190
Maximising a weighted product
1905
191
Prize Strings
3256
192
Best Approximations
735
193
Squarefree Numbers
1405
194
Coloured Configurations
655
195
Inscribed circles of triangles with one angle of 60 degrees
623
196
Prime triplets
1049
197
Investigating the behaviour of a recursively defined sequence
2472
198
Ambiguous Numbers
541
199
Iterative Circle Packing
847
200
Find the 200th prime-proof sqube containing the contiguous sub-string "200"
1011