cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A232800 Denominators written by antidiagonals of interleaved A063524(n) and A002427(n)/A006955(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 2, 1, 2, 1, 6, 6, 3, 3, 6, 6, 1, 6, 3, 1, 3, 6, 1, 6, 6, 1, 3, 3, 1, 6, 6, 1, 6, 3, 3, 1, 3, 3, 6, 1, 10, 10, 15, 5, 15, 15, 5, 15, 10, 10, 1, 10, 5, 15, 15, 1, 15, 15, 5, 10, 1
Offset: 0

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Author

Paul Curtz, Nov 30 2013

Keywords

Comments

The numerators of Br(n)=0, 1, 1, 1/2, 0, -1/6, 0, 1/6, 0, -3/10, 0, 5/6, 0,... are in A229979(n).
(Corresponding complementary Euler numbers Er(n):
A198631(2n+1)/A006519(2n+2)=1/2, -1/4, 1/2, -17/8, 31/2, -691/4,... =Ef2(n). (2*n+2)*Ef2(n)=1, -1, 3, -17, 155, 2073,...=-A001469(n+1),Genocchi numbers. Er(n)=interleaved (A063524(n) and -A001469(n+1)) =0, 1, 1, -1, 0, 3, 0, -17, 0, 155,... =-A226158(n).)

Examples

			1,
1, 1,
1, 1, 1,
2, 2, 2, 2,
1, 2, 1, 2, 1,
6, 6, 3, 3, 6, 6, etc.
Triangle of denominators of Br(n),complementary Bernoulli numbers,written by antidiagonals (see A229979).
		

A242246 Numerators of n*A164555(n-1)/A027642(n-1).

Original entry on oeis.org

0, 1, 1, 1, 0, -1, 0, 1, 0, -3, 0, 5, 0, -691, 0, 35, 0, -3617, 0, 43867, 0, -1222277, 0, 854513, 0, -1181820455, 0, 76977927, 0, -23749461029, 0, 8615641276005, 0, -84802531453387, 0, 90219075042845, 0
Offset: 0

Views

Author

Paul Curtz, May 09 2014

Keywords

Comments

First multiplied shifted (second) Bernoulli numbers.
A164555(n-1)/A027642(n-1) = 0 followed by (A164555(n)/A027642(n)=1, 1/2, 1/6,...) = f(n) = 0, 1, 1/2, 1/6, 0,... .
f(n+1) - f(n) = A051716(n)/A051717(n).
Generally we consider a transform applied to the autosequences of first or second kind. An autosequence is a sequence which has its inverse binomial transform equal to the signed sequence. It is of the first kind if the main diagonal is A000004=0's. It is of the second kind if the main diagonal is the first upper diagonal multiplied by 2. A000045(n) is an autosequence of the first kind. A164555(n)/A027642(n) is an autosequence of the second kind. See A190339 (and A241269).
Here we apply the transform to the Bernoulli numbers A164555(n)/A027642(n).
We take n*(0 followed by A164555(n)/A027642(n)).
Hence the autosequence of first kind
TB1(n) = 0, 1, 1, 1/2, 0, -1/6, 0, 1/6, 0, -3/10, 0, 5/6, O, -691/210,.. .
a(n) are the numerators.
The first seven rows of the differencece table of TB1(n) are
0, 1, 1, 1/2, 0, - 1/6, 0, 1/6,...
1, 0, -1/2, -1/2, -1/6, 1/6, 1/6, -1/6,... =A140351(n+1)/b(n+1)
-1, -1/2, 0, 1/3, 1/3, 0, -1/3, -2/15,...
1/2, 1/2, 1/3, 0, -1/3, -1/3, 1/5, 11/15,...
0, -1/6, -1/3, -1/3, 0, 8/15, 8/15, -4/5,...
-1/6, -1/6, 0, 1/3, 8/15, 0, -4/3, -4/3,...
0, 1/6, 1/3, 1/5, -8/15, -4/3, 0, 512/105,... .
First and second upper diagonals: 1, -1/2, 1/3, -1/3, 8/15, -4/3, 512/105,... .
Sum of the antidiagonals:
0, 1, 1, 0, -1/2, 0, 1/2, 0, -5/6, 0, 13/6, 0, -49/6, 0,... .
(Note that the same transform applied to the second fractional Euler numbers A198631(n)/A006519(n+1) yields the Genocchi numbers -A226158(n)).
This transform can be continued:
TB2(n) = n*(0 followed by TB1(n)) =
0, 0, 2, 3, 2, 0, -1, 0, 4/3, 0, -3, 0, 10, 0, -691/15, 0, 280, 0,...
is an autosequence of second kind.
TB3(n) = 0, 0, 0, 6, 12, 10, 0, -7, 0, 12, 0, -33, 0, 130, 0, 691, 0,...
is apparently an integer autosequence of the first kind.

Crossrefs

Cf. A199969 (autosequence).

Formula

a(n) = 0 followed by (A050925(n) = 1, -1, 1, 0,... ) with 1 instead of -1.
a(2n) = A063524(n). a(2n+1) = A002427(n).
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