This site is supported by donations to The OEIS Foundation.

# User:Matej Veselovac

Jump to: navigation, search

The OEIS has a lot of cool sequences. Here are some examples I dabbled with:

 ■ Some sequences which hide Sierpińsk-ish fractals: A080099 (bitwise logical AND) A080098 (bitwise logical OR) A327853 (Sierpiński's triangle × triangular numbers) A327889 (Pascal's triangle ° digit transformation) A327742 (prime combinations) ■ Noteworthy rare primes (conjectured to be infinite): A088164 (Wolstenholme primes) A001220 (Wieferich primes) A007540 (Wilson primes) A000000 (Wall-Sun-Sun primes - none are known) ■ Consecutive palindromes problem: A279092 (k>=2, the double palindromes) A279093 (k>=3, the triple palindromes) A323742 (k=3, the existence problem) A333512 (k=3, but no other palindromic bases) A327810 (irregular consecutive palindromes) ■ Number formation with basic operations (+,-,*,/) problem: A142153 (use integers at most once) A309885 (use integers exactly once) A309886 (use powers of two exactly once) ■ Memorable "Jumping" sequences: A006370 (The Collatz map) A005132 (Recamán's sequence) A329230 (Grasshopper tour) ■ Counting on Circles: A250001 (arrangements in affine plane) A067310 (chords with k simple intersections) A331702 (intersections on polygons) ■ Counting with Dominoes: A004003 (count domino tilings of 2n X 2n square) A333837 (count ways to collapse a triangular formation) ■ Sums of (unordered) factorizations: A337037 (numbers with all unique sums) A337080 (numbers with some duplicate sums) A337081 (primitive complement of such numbers) ■ Puzzle-related sequences: A334911 (Census-taker numbers) A334916 (base n baseless numbers) A337670, A337671 (base-exponent invariants)