A276755 a(n) = A275706(n)^2 + A276688(n)^2 = [n]{1+i}! * [n]{1-i}!, where [n]_q! is the q-factorial, i = sqrt(-1).

1, 1, 5, 65, 1625, 66625, 4330625, 489360625, 110106140625, 52961053640625, 54285079981640625, 114704374001206640625, 484625980155098056640625, 4032572780870570929306640625

Offset: 0

Author

Vladimir Reshetnikov, Sep 16 2016

Keywords

• nonn

Crossrefs

Cf. A275706, A276688, A038505.

Programs

Mathematica

Table[QFactorial[n, 1 + I] QFactorial[n, 1 - I], {n, 0, 20}]

Formula

a(n) = |[n]_{1+i}!|^2.

a(n+1)/a(n) = 4*A038505(n) + 1.