login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A163938 Triangle related to the o.g.f.s. of the right hand columns of A163932 (E(x, m=3, n)). 7
1, 3, 3, 11, 28, 6, 50, 225, 135, 10, 274, 1858, 2092, 486, 15, 1764, 16464, 29148, 13482, 1491, 21, 13068, 158352, 398640, 301220, 70485, 4152, 28, 109584, 1655172, 5552724, 6132780, 2432070, 322971, 10863, 36 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The asymptotic expansions of the higher order exponential integral E(x, m=3, n) lead to triangle A163932, see A163931 for information on the E(x,m,n). The o.g.f.s. of the right hand columns of triangle A163932 have a nice structure Gf(p) = W3(z,p)/(1-z)^(2*p+1) with p = 1 for the first right hand column, p = 2 for the second right hand column, etc. The coefficients of the W3(z,p) polynomials lead to the triangle given above, n >= 1 and 1 <= m <= n. The row sums of this triangle lead to A001879, see A163936 for more information.

LINKS

G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened

FORMULA

a(n,m) = Sum_{k=0..(m-1)} (-1)^(n+k+1)*binomial(m-k+1,2) *binomial(2*n+1,k) *stirling1(m+n-k,m-k+1), for 1 <= m <= n.

EXAMPLE

The first few W3(z,p) polynomials are:

W3(z,p=1) = 1/(1-z)^3

W3(z,p=2) = (3 + 3*z)/(1-z)^5

W3(z,p=3) = (11 + 28*z + 6*z^2)/(1-z)^7

W3(z,p=4) = (50 + 225*z + 135*z^2 + 10*z^3)/(1-z)^9

MAPLE

with(combinat): a := proc(n, m): add((-1)^(n+k+1)*((m-k+1)*(m-k)/2!)*binomial(2*n+1, k)*stirling1(m+n-k, m-k+1), k=0..m-1) end: seq(seq(a(n, m), m=1..n), n=1..8); # Johannes W. Meijer, revised Nov 27 2012

MATHEMATICA

Table[Sum[(-1)^(n + k + 1)*Binomial[m - k + 1, 2]*Binomial[2*n + 1, k]*StirlingS1[m + n - k, m - k + 1], {k, 0, m - 1}], {n, 1, 50}, {m, 1, n}] // Flatten (* G. C. Greubel, Aug 13 2017 *)

PROG

(PARI) for(n=1, 10, for(m=1, n, print1(sum(k=0, m-1, (-1)^(n+k+1)* binomial(m-k+1, 2)*binomial(2*n+1, k) *stirling(m+n-k, m-k+1, 1)) , ", "))) \\ G. C. Greubel, Aug 13 2017

CROSSREFS

Row sums equal A001879.

A000254 equals the first left hand column.

A000217 equals the first right hand column.

Cf. A163931 (E(x,m,n)) and A163932.

Cf. A163936 (E(x,m=1,n)), A163937 (E(x,m=2,n)) and A163939 (E(x,m=4,n)).

Sequence in context: A281101 A322701 A124265 * A109937 A054101 A176956

Adjacent sequences:  A163935 A163936 A163937 * A163939 A163940 A163941

KEYWORD

easy,nonn,tabl

AUTHOR

Johannes W. Meijer, Aug 13 2009

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 12 10:02 EDT 2020. Contains 335657 sequences. (Running on oeis4.)