bibkey: granvik2008a145110
authors: Mats Granvik
year: 2008
title: "OEIS A145110, Number of elements in the Redheffer matrix that contribute to the Moebius function"
doi: null
url: https://oeis.org/A145110
claim: "a(11) to a(30) are conjectured to be 11, 23, 13, 18, 19, 25, 17, 29, 19, 30, 26, 26, 23, 45, 27, 30, 32, 39, 29, 48. [From _Mats Granvik_, Dec 21 2008]"
strata_touched:
  - D5/S3/Arith/GranvikRedhefferSupport
license: citation-only
triage: anchor

OEIS A145110

Granvik’s entry counts matrix positions occurring in at least one nonzero permutation term for the Möbius variant of the Redheffer matrix. Its example at n=8 displays 13 contributing positions and identifies the rows associated with divisors of 8. The displayed array uses the transpose of the convention B(i,j)=1 when j=1 or i divides j, with B(n,n)=0.

The cross-reference A143104 specifies the modification at (n,n) and its Möbius determinant for n>1. A008683 reproduces the attributed determinant argument. These determinant statements concern signed sums of permutation terms; A145110 counts the union of their positions.

The data section lists the first ten terms. Revision 7 retains the twenty conjectured values in the comment quoted in the frontmatter. Its extension note attributes their relocation from the data section to N. J. A. Sloane. The n=1 datum is outside the range of the conjectured list: the literal modified-matrix convention gives no contributing position there, whereas the entry lists 1.

Verified locator

• Declared URL: https://oeis.org/A145110
• Pinned official export: https://github.com/oeis/oeisdata/blob/72c53dd50967ac7166f7d31bf79be95174ec5bc6/seq/A145/A145110.seq
• The current official GitHub export and the pinned export both identify revision #7 May 22 2014 23:29:40 and contain the quoted comment verbatim.
• The direct OEIS search and internal-page endpoints returned HTTP 403; the verified text is the official GitHub export.
• Related definition: https://github.com/oeis/oeisdata/blob/72c53dd50967ac7166f7d31bf79be95174ec5bc6/seq/A143/A143104.seq
• Related determinant argument: https://github.com/oeis/oeisdata/blob/72c53dd50967ac7166f7d31bf79be95174ec5bc6/seq/A008/A008683.seq

Only bibliographic information and the conjecture needed to identify the mathematical claim are quoted; no license to redistribute the full OEIS entry is asserted.