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.

Showing 1-3 of 3 results.

A364069 Dowling numbers: e.g.f. exp(x + (exp(b*x)-1)/b) with b = 63.

Original entry on oeis.org

1, 2, 67, 4355, 295234, 21036803, 1625419909, 140823067772, 13947448935109, 1570142163116087, 196457384808738412, 26717651072732512841, 3896182904620308595021, 605803757139146097600266, 100236348400243756326661039, 17619174544126256877550593743, 3280792242500933388439611444802
Offset: 0

Views

Author

Stefano Spezia, Jul 04 2023

Keywords

Comments

a(n) is the number of all 64-subgroups of R^n, where R^n is a near-vector space over a proper nearfield R.

Crossrefs

Cf. A000110 (b=1), A007405 (b=2), A003575 (b=3), A003576 (b=4), A003577 (b=5), A003578 (b=6), A003579 (b=7), A003580 (b=8), A003581 (b=9), A003582 (b=10), A364070 (b=624).
Row sums of the triangle A364072.
2nd row of the array A364074.

Programs

  • Mathematica
    With[{m=16, b=63}, CoefficientList[Series[Exp[x +(Exp[b*x]-1)/b], {x, 0, m}], x]*Range[0, m]!] (* or *)
    a[n_]:=Sum[Sum[Binomial[n,d]StirlingS2[n-d,k]63^(n-d-k),{d,0,n-k}],{k,0,n}]; Array[a,17,0]

Formula

E.g.f.: exp(x + (exp(63*x) - 1)/63).
a(n) = exp(-1/63) * Sum_{k>=0} (63*k + 1)^n / (63^k * k!).
a(n) ~ 63^(n + 1/63) * n^(n + 1/63) * exp(n/LambertW(63*n) - n - 1/63) / (sqrt(1 + LambertW(63*n)) * LambertW(63*n)^(n + 1/63)).
a(n) = Sum_{k=0..n} Sum_{d=0..n-k} binomial(n, d)*StirlingS2(n-d, k)*63^(n-d-k).

A364073 Triangle read by rows: T(n, k) = Sum_{d=0..n-k} binomial(n, d)*StirlingS2(n-d, k)*624^(n-d-k), with 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 626, 1, 1, 391251, 1875, 1, 1, 244531876, 2733126, 3748, 1, 1, 152832422501, 3658206250, 9753130, 6245, 1, 1, 95520264063126, 4721932028751, 21925818740, 25346895, 9366, 1, 1, 59700165039453751, 5993213367973125, 45788990528771, 85217015555, 54578181, 13111, 1
Offset: 0

Views

Author

Stefano Spezia, Jul 04 2023

Keywords

Comments

T(n, k) is the number of 625-subgroups of R^n which have dimension k, where R^n is a near-vector space over a proper nearfield R.

Examples

			The triangle begins:
  1;
  1,            1;
  1,          626,          1;
  1,       391251,       1875,       1;
  1,    244531876,    2733126,    3748,    1;
  1, 152832422501, 3658206250, 9753130, 6245, 1;
  ...
		

Crossrefs

Cf. A000012 (k=0), A364070 (row sums), A364071, A364072.

Programs

  • Mathematica
    T[n_,k_]:=Sum[Binomial[n,d]StirlingS2[n-d,k]624^(n-d-k),{d,0,n-k}]; Table[T[n,k],{n,0,7},{k,0,n}]//Flatten

A364071 Triangle read by rows: T(n, k) = Sum_{d=0..n-k} binomial(n, d)*StirlingS2(n-d, k)*8^(n-d-k), with 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 10, 1, 1, 91, 27, 1, 1, 820, 550, 52, 1, 1, 7381, 10170, 1850, 85, 1, 1, 66430, 180271, 56420, 4655, 126, 1, 1, 597871, 3131037, 1590771, 210035, 9821, 175, 1, 1, 5380840, 53825500, 42900312, 8521926, 612696, 18396, 232, 1, 1, 48427561, 920414340, 1126333300, 324123870, 33642462, 1514100, 31620, 297, 1
Offset: 0

Views

Author

Stefano Spezia, Jul 04 2023

Keywords

Comments

T(n, k) is the number of 8-subgroups of R^n which have dimension k, where R^n is a near-vector space over a proper nearfield R.

Examples

			The triangle begins:
  1;
  1,      1;
  1,     10,       1;
  1,     91,      27,      1;
  1,    820,     550,     52,       1;
  1,   7381,   10170,   1850,      85,    1;
  1,  66430,  180271,  56420,    4655,  126,   1;
  1, 597871, 3131037, 1590771, 210035, 9821, 175, 1;
  ...
		

Crossrefs

Cf. A000012 (k=0), A002452 (k=1), A003580 (row sums), A364072, A364073.

Programs

  • Mathematica
    T[n_,k_]:=Sum[Binomial[n,d]StirlingS2[n-d,k]8^(n-d-k),{d,0,n-k}]; Table[T[n,k],{n,0,9},{k,0,n}]//Flatten
Showing 1-3 of 3 results.