login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A227608 Denominators of A225825(n) difference table written by antidiagonals. 2
1, 2, 2, 6, 3, 6, 2, 3, 3, 2, 30, 15, 15, 15, 30, 2, 15, 15, 15, 15, 2, 42, 21, 105, 105, 105, 21, 42, 2, 21, 21, 105, 105, 21, 21, 2, 30, 15, 105, 105, 105, 105, 105, 15, 30, 2, 15, 15, 105, 105, 105, 105, 15, 15, 2, 66, 33, 165, 165, 1155, 231, 1155, 165, 165, 33, 66, 2, 33, 33, 165, 165, 231, 231, 165, 165, 33, 33, 2 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..77.

EXAMPLE

1,

-1/2,      1/2,

-1/6,     -2/3,     -1/6,

1/2,       1/3,     -1/3,     -1/2,

7/30,    11/15,    16/15,    11/15,     7/30,

-3/2,   -19/15,    -8/15,     8/15,    19/15,    3/2,

-31/42, -47/21, -368/105, -424/105, -368/105, -47/21, -31/42.

Row sums: 1, 0/2, -6/6, 0/6, 90/30, 0/30, -3570/210, 0/210, 32550/210,... .

Are the denominators A034386(n+1)?

Reduced row sums: 1, 0, -1, 0, 3, 0, -17, 0, 155,... = -A036968(n+1)? See A226158(n+2). First 100 terms checked by Jean-François Alcover.

MATHEMATICA

max = 12; b[0] = 1; b[n_] := Numerator[ BernoulliB[n, 1/2] - (n+1)*EulerE[n, 0]]; t = Table[b[n], {n, 0, max}] / Table[ Sum[ Boole[ PrimeQ[d+1]]/(d+1), {d, Divisors[n]}] // Denominator, {n, 0, max}]; dt = Table[ Differences[t, n], {n, 0, max}]; Table[ dt[[n-k+1, k]] // Denominator, {n, 1, max}, {k, 1, n}] // Flatten (* Jean-François Alcover, Aug 12 2013 *)

CROSSREFS

Cf. A085738

Sequence in context: A275037 A174833 A085738 * A276484 A100641 A028421

Adjacent sequences:  A227605 A227606 A227607 * A227609 A227610 A227611

KEYWORD

nonn,frac,tabl

AUTHOR

Paul Curtz, Aug 10 2013

EXTENSIONS

More terms from Jean-François Alcover, Aug 12 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 21 17:06 EDT 2018. Contains 316427 sequences. (Running on oeis4.)