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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.

A347354 a(n) = sum of T(n,k) - T(n-1,k) for row n of A347285.

Original entry on oeis.org

1, 2, 1, 3, 4, 1, 2, 5, 1, 6, 1, 2, 7, 1, 3, 2, 1, 8, 1, 4, 2, 1, 9, 10, 1, 2, 11, 1, 3, 1, 2, 12, 1, 4, 13, 1, 2, 1, 14, 15, 1, 2, 3, 1, 6, 2, 1, 4, 1, 16, 2, 1, 17, 18, 1, 2, 1, 3, 5, 1, 2, 19, 1, 4, 2, 1, 20, 1, 3, 21, 1, 2, 22, 1, 9, 1, 2, 4, 1, 8, 2, 1, 3
Offset: 1

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Author

Michael De Vlieger, Sep 16 2021

Keywords

Comments

If for row n, k > A089576(n-1), we interpret T(n-1,k) = 0.
Also the length of d = T(n,k) - T(n-1,k) in row n of A347285 such that d > 1, with 0 <= d <= 1.
Compactification of A347284 via indices k of primorials A002110(k). This is the most efficient compactification of A347284, superior to binary compactification via A347287. It employs the fact that A347284 concerns products of primorials, i.e., is a subset of A025487.
We can construct row n of A347285 by summing a constant array of a(k) 1's for 1 <= k <= n-1.

Examples

			Relation of a(n) and irregular triangle A347285, placing "." after the term in the current row where T(n,k) no longer exceeds T(n-1,k). Since the rows of A347285 reach a fixed point of 0, we interpret T(n,k) for vacant T(n-1,k) as exceeding same.
n    Row n of A347285   a(n)
-----------------------------
0:    0
1:    1.                   1
2:    2  1.                2
3:    3. 1                 1
4:    4  2  1.             3
5:    5  3  2  1.          4
6:    6. 3  2  1           1
7:    7  4. 2  1           2
8:    8  5  3  2  1.       5
9:    9. 5  3  2  1        1
10:  10  6  4  3  2  1.    6
...
a(3) = 1 since row 3 of A347285 has {3,1} while row 2 has {2,1}; only the first term of the former exceeds the analogous term in the latter.
a(4) = 3 since row 4 = {4,2,1} and row 3 = {3,1}; all 3 terms of the former are larger than the analogous term in the latter, etc.
		

Crossrefs

Programs

  • Mathematica
    Block[{nn = 84, a = {0}, c, e, m}, e[1] = 0; Do[c = 1; e[1]++; Do[Set[m, j]; Which[e[j - 1] == 1, Break[], IntegerQ@ e[j], If[e[j] < #, e[j]++; c++] &@ Floor@ Log[Prime[j], Prime[j - 1]^e[j - 1]], True, Set[e[j], 1]], {j, 2, k}]; AppendTo[a, c + Boole[c == m - 2]], {k, 2, nn}]; MapAt[# - 1 &, a, 4]]

Formula

A347284(n) = Product_{k=1..n} A002110(a(k)).