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

0,3

Links

Table of n, a(n) for n=0..13.

Formula

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

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

Mathematica

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

Crossrefs

Cf. A275706, A276688, A038505.

Sequence in context: A370261 A251575 A277347 * A346115 A218221 A046881

Adjacent sequences: A276752 A276753 A276754 * A276756 A276757 A276758

Keyword

nonn

Author

Vladimir Reshetnikov, Sep 16 2016

Status

approved