login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A308502 Square array A(n,k), n >= 1, k >= 0, read by antidiagonals: A(n,k) = Sum_{d|n} d^(n/d + k). 4

%I #19 May 11 2021 01:55:06

%S 1,1,3,1,5,4,1,9,10,9,1,17,28,25,6,1,33,82,81,26,24,1,65,244,289,126,

%T 80,8,1,129,730,1089,626,330,50,41,1,257,2188,4225,3126,1604,344,161,

%U 37,1,513,6562,16641,15626,8634,2402,833,163,68,1,1025,19684,66049,78126,49100,16808,5249,973,290,12

%N Square array A(n,k), n >= 1, k >= 0, read by antidiagonals: A(n,k) = Sum_{d|n} d^(n/d + k).

%H Seiichi Manyama, <a href="/A308502/b308502.txt">Antidiagonals n = 1..140, flattened</a>

%F L.g.f. of column k: -log(Product_{j>=1} (1 - j*x^j)^(j^(k-1))).

%e Square array begins:

%e 1, 1, 1, 1, 1, 1, ...

%e 3, 5, 9, 17, 33, 65, ...

%e 4, 10, 28, 82, 244, 730, ...

%e 9, 25, 81, 289, 1089, 4225, ...

%e 6, 26, 126, 626, 3126, 15626, ...

%e 24, 80, 330, 1604, 8634, 49100, ...

%t T[n_, k_] := DivisorSum[n, #^(n/# + k) &]; Table[T[k, n - k], {n, 1, 11}, {k, 1, n}] // Flatten (* _Amiram Eldar_, May 11 2021 *)

%Y Columns k=0..2 give A055225, A078308, A296601.

%Y Cf. A279394, A308504.

%K nonn,tabl

%O 1,3

%A _Seiichi Manyama_, Jun 02 2019

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 18 22:18 EDT 2024. Contains 371782 sequences. (Running on oeis4.)