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.

A141018 a(n) is the largest number in the n-th row of triangle A140997.

Original entry on oeis.org

1, 1, 2, 4, 8, 15, 28, 52, 96, 177, 345, 694, 1386, 2751, 5431, 10672, 20885, 40724, 79153, 153402, 296528, 571845, 1129293, 2264749, 4527029, 9021498, 17926740, 35527082, 70230422, 138504765, 272545323, 535184340, 1048842743, 2051669285, 4006253136, 7954830148
Offset: 0

Views

Author

Juri-Stepan Gerasimov, Jul 11 2008

Keywords

Comments

Also the largest number of the n-th row of A140994.

Examples

			The largest number of 1 is a(0) = 1.
The largest number of 1 1 is a(1) = 1.
The largest number of 1 2 1 is a(2) = 2.
The largest number of 1 4 2 1 is a(3) = 4.
The largest number of 1 8 4 2 1 is a(4) = 8.
The largest number of 1 15 9 4 2 1 is a(5) = 15.
The largest number of 1 28 19 9 4 2 1 is a(6) = 28.
The largest number of 1 52 40 19 9 4 2 1 is a(7) = 52.
		

Crossrefs

Programs

  • Maple
    A140997 := proc(n,k) option remember ; if k<0 or k>n then 0 ; elif k=0 or k=n then 1 ; elif k=n-1 then 2 ; elif k=n-2 then 4 ; else procname(n-1,k)+procname(n-2,k)+procname(n-3,k)+procname(n-3,k-1) ; fi; end:
    A141018 := proc(n) max(seq(A140997(n,k),k=0..n)) ; end: for n from 0 to 60 do printf("%d,",A141018(n)) ; od: # R. J. Mathar, Sep 19 2008
  • Mathematica
    T[n_, k_] := T[n, k] = Which[k < 0 || k > n, 0, k == 0 || k == n, 1, k == n-1, 2, k == n-2, 4, True, T[n-1, k]+T[n-2, k]+T[n-3, k]+T[n-3, k-1]];
    a[n_] := Max[Table[T[n, k], {k, 0, n}]];
    Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Oct 18 2023, after R. J. Mathar *)

Extensions

Partially edited by N. J. A. Sloane, Jul 18 2008
Simplified definition, corrected from a(12) on and extended by R. J. Mathar, Sep 19 2008