23 December

Permanent link to this puzzle:
This number is a prime number. If you treble it and add 16, the result is also prime. Repeating this will give 11 prime numbers in total (including the number itself).


Show me a random puzzle
 Most recent collections 

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

Sunday Afternoon Maths LXV

Cryptic crossnumber #1
Breaking Chocolate
Square and cube endings

List of all puzzles


hexagons digits cards crosswords doubling advent perfect numbers triangle numbers star numbers complex numbers bases scales palindromes polygons square roots time sums planes functions angles proportion percentages dates sport pascal's triangle volume ave triangles symmetry folding tube maps 2d shapes coordinates spheres cryptic clues indices ellipses perimeter chocolate prime numbers speed sum to infinity colouring squares multiples remainders taxicab geometry trigonometry circles games floors fractions parabolas algebra numbers averages integers factors rectangles arrows graphs square numbers chalkdust crossnumber rugby cube numbers number dice partitions quadratics factorials division wordplay calculus shape coins menace crossnumbers geometry probability unit fractions lines multiplication differentiation odd numbers balancing irreducible numbers routes probabilty logic regular shapes books money surds integration area 3d shapes cryptic crossnumbers sequences grids clocks shapes mean dodecagons christmas means addition chess people maths


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2019