A228838 a(n) = n * A002445(n).

0, 6, 60, 126, 120, 330, 16380, 42, 4080, 7182, 3300, 1518, 32760, 78, 12180, 214830, 8160, 102, 34545420, 114, 270600, 37926, 15180, 6486, 1113840, 1650, 41340, 21546, 24360, 10266, 1703601900, 186, 16320, 2135826, 1020, 164010, 5043631320, 222, 1140

Offset: 0

Author

Paul Curtz, Sep 05 2013

Keywords

• nonn

Comments

a(n+1) is a multiple of A040031(n+1), sequence of period 2: 6, 12.

a(n) is divisible by A040879(n)=30 followed by the sequence of period 2: 6, 60. See A040214 and A165734.

Note that A164877(n) + A000367(n) = A164558(2n).

Examples

			a(0)=0*1, a(1)=1*6, a(2)=2*30=60,, a(3)=3*42=126.
		

Links

• Colin Barker, Table of n, a(n) for n = 0..1000

Programs

PARI

a(n)=n*denominator(bernfrac(2*n))

Formula

a(n) = A176328(2n) - A000367(n).

a(n) = A164877(n)/2.

a(n+1) = A111008(n) * A036283(n+1).

2*a(n) = A164558(2n) - A000367(n).

a(n) = A164558(2n) - A176328(2n).

Extensions

Typo in data fixed by Colin Barker, Jul 03 2015