Number of essentially different ways in which the squares 1,4,9,...,n^2 can be arranged in a sequence such that all pairs of adjacent squares sum to a prime number. Rotations and reversals are counted only once.

A073451

Number of essentially different ways in which the squares 1,4,9,...,n^2 can be arranged in a sequence such that all pairs of adjacent squares sum to a prime number. Rotations and reversals are counted only once.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =0a(7) =12a(8) =6a(9) =66a(10) =156a(11) =44a(12) =312a(13) =1484a(14) =2672a(15) =6680a(16) =19080a(17) =45024a(18) =168496a(19) =2033271a(20) =724543a(21) =2776536a(22) =24598062a(23) =26849699a(24) =345160845a(25) =4478968678a(26) =5094833662a(27) =14184530127a(28) =29116554754a(29) =125878922175

External references