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Problems


IDDescription / TitleSolved By
151
Paper sheets of standard sizes: an expected-value problem.
2443
152
Writing 1/2 as a sum of inverse squares
1213
153
Investigating Gaussian Integers
1168
154
Exploring Pascal's pyramid.
1234
155
Counting Capacitor Circuits.
1634
156
Counting Digits
1105
157
Solving the diophantine equation 1/a+1/b= p/10n
1252
158
Exploring strings for which only one character comes lexicographically after its neighbour to the left.
1738
159
Digital root sums of factorisations.
1565
160
Factorial trailing digits
1544
161
Triominoes
983
162
Hexadecimal numbers
2726
163
Cross-hatched triangles
915
164
Numbers for which no three consecutive digits have a sum greater than a given value.
2816
165
Intersections
1247
166
Criss Cross
1986
167
Investigating Ulam sequences
844
168
Number Rotations
1288
169
Exploring the number of different ways a number can be expressed as a sum of powers of 2.
2190
170
Find the largest 0 to 9 pandigital that can be formed by concatenating products.
959
171
Finding numbers for which the sum of the squares of the digits is a square.
1257
172
Investigating numbers with few repeated digits.
1851
173
Using up to one million tiles how many different "hollow" square laminae can be formed?
4521
174
Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements.
3014
175
Fractions involving the number of different ways a number can be expressed as a sum of powers of 2.
940
176
Rectangular triangles that share a cathetus.
970
177
Integer angled Quadrilaterals.
657
178
Step Numbers
1706
179
Consecutive positive divisors
5687
180
Rational zeros of a function of three variables.
795
181
Investigating in how many ways objects of two different colours can be grouped.
952
182
RSA encryption
1286
183
Maximum product of parts
2500
184
Triangles containing the origin.
787
185
Number Mind
1552
186
Connectedness of a network.
1405
187
Semiprimes
5550
188
The hyperexponentiation of a number
3380
189
Tri-colouring a triangular grid
1008
190
Maximising a weighted product
2095
191
Prize Strings
3547
192
Best Approximations
799
193
Squarefree Numbers
1549
194
Coloured Configurations
725
195
Inscribed circles of triangles with one angle of 60 degrees
673
196
Prime triplets
1179
197
Investigating the behaviour of a recursively defined sequence
2687
198
Ambiguous Numbers
578
199
Iterative Circle Packing
930
200
Find the 200th prime-proof sqube containing the contiguous sub-string "200"
1120