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# User:John Mason

B.A. in Mathematics at University of York(UK) 1978. Retired as of 1 Feb 2021. In December 2021 I calculated the number of free polyominoes (A000105) through to size 48 (and in April 2023 to size 50), building on previous work by I.Jensen and Robert A.Russell. On the subject of polyominoes, please write to me at theillustratedpolyomino (at) gmail.com.

Sequences I have inserted:

A307503 Least prime containing at least n consecutive 1's in its binary representation.

A322097 a(1)=1, a(2)=1; for n > 2, a(n) is the largest proper divisor of the concatenation of terms a(1) through a(n-1).

A322098 a(1)=1, a(2)=1; for n > 2, a(n) is the largest noncomposite proper divisor of the concatenation of terms a(1) through a(n-1).

A318826 a(n) is the first prime p that starts a run of length n of multiples of itself in alternate terms of A254077.

A291806 The number of polyomino tilings of n X n square.

A291807 The number of symmetric polyomino tilings of n X n square.

A291808 Number of tilings of an n X n square using distinct polyominoes.

A291809 Number of tilings of n X n square using differently sized polyominoes.

A277565 Number of flattenable free polyominoids

A268371 Triangle read by rows: T(n,k) is the number of free polyominoes with width n and height k.

A268427 Number of polyominoes that will fit in a square of size n X n

A268416 Number of aligned free polyominoes that will fit in a square of size n X n.

A234013 Number of maximally biased free polyominoes with n squares

A234599 Number of n-celled solid polyominoes (or free polycubes, allowing mirror-image identification) with chessboard coloring.

A234006 Free polyominoes with 2n squares, having reflectional symmetry on axis that coincides with edges

A234007 Free polyominoes with 4n squares, having 90 degree rotational symmetry about a square corner, but not having reflectional symmetry on axis that coincides with edges

A234008 Free polyominoes with 2n squares, having 180 degree rotational symmetry about a square mid-side, but not having reflectional symmetry on axis that coincides with edges

A234009 Free polyominoes with 4n squares, having 90 degree rotational symmetry about a square corner

A234010 Free polyominoes with 2n squares, having 180-degree rotational symmetry about a square mid-side

A234012 Number of unbiased free polyominoes with 2n squares

Sequences to which I have contributed:

A075679

A254077

A256213

A256404

A166133

A256409

A256406

A256408

A256403

A256405

A001065

A007434

A134675

A134673

A134675

A127448

A246559

A121198

A001071

A106249

A001933

A322323