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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A244128 Triangle read by rows: coefficients T(n,k) of a binomial decomposition of 0^(n-1) as Sum(k=0..n)T(n,k)*binomial(n,k).

Original entry on oeis.org

0, 1, 0, 1, -2, 0, 1, -4, 9, 0, 1, -8, 27, -64, 0, 1, -16, 81, -256, 625, 0, 1, -32, 243, -1024, 3125, -7776, 0, 1, -64, 729, -4096, 15625, -46656, 117649, 0, 1, -128, 2187, -16384, 78125, -279936, 823543, -2097152, 0, 1, -256, 6561, -65536, 390625, -1679616, 5764801, -16777216, 43046721
Offset: 1

Views

Author

Stanislav Sykora, Jun 22 2014

Keywords

Comments

T(n,k)=(-k)^(k-1)*k^(n-k) for k>0, while T(n,0)=0 by convention. The flattened triangle start with row 1, coefficient T(1,0).
Resembles A076014, but with added powers of 0, and with sign-alternating columns.

Examples

			The first rows of the triangle (starting at n=1):
0, 1,
0, 1, -2,
0, 1, -4, 9,
0, 1, -8, 27, -64,
0, 1, -16, 81, -256, 625,
0, 1, -32, 243, -1024, 3125, -7776,
		

Crossrefs

Programs

  • PARI
    seq(nmax,b)={my(v,n,k,irow);
    v = vector((nmax+1)*(nmax+2)/2-1);
    for(n=1,nmax,irow=n*(n+1)/2;v[irow]=0;
      for(k=1,n,v[irow+k]=(-1)^(k-1)*(k*b)^(n-1);););
    return(v);}
    a=seq(100,1);

A076015 Sum of the (n-1)-th powers of the first n integers.

Original entry on oeis.org

1, 3, 14, 100, 979, 12201, 184820, 3297456, 67731333, 1574304985, 40851766526, 1170684360924, 36720042483591, 1251308658130545, 46034015337733480, 1818399978159990976, 76762718946972480009
Offset: 1

Views

Author

Wolfdieter Lang, Oct 02 2002

Keywords

Comments

a(n) is the number of length n sequences of [n] that start with their maximum value.
By symmetry, counts many other simple classes of endofunctions.

Examples

			The 3 sequences for n=2 are 11, 21, 22.
The 14 = 3^0 + 3^1 + 3^2 sequences starting with their maximum value for n=3 are 111, 211, 212, 221, 222, 311, 312, 313, 321, 322, 323, 331, 332, 333.
		

Crossrefs

Cf. A076014.
A diagonal of array A103438.
A subset of A000312.

Programs

Formula

a(n) = Sum_{m=1..n} m^(n-1), n >= 1.

Extensions

Definition changed and example added by Olivier Gérard, Jan 28 2023
Showing 1-2 of 2 results.