Smallest positive number of "triangular" shuffles of n(n+1)/2 cards needed to restore them to their original order.

A122158

Smallest positive number of "triangular" shuffles of n(n+1)/2 cards needed to restore them to their original order.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =20a(4) =18a(5) =12a(6) =126a(7) =33a(8) =204a(9) =1638a(10) =1968a(11) =2010a(12) =504a(13) =17043a(14) =240a(15) =222870a(16) =4084080a(17) =12462a(18) =81396a(19) =4200a(20) =41790a(21) =24254a(22) =56560a(23) =1377090a(24) =30669496a(25) =57420a(26) =249480a(27) =93840a(28) =696010a(29) =40680

External references