# Questions tagged [oeis]

For questions related to the On-Line Encyclopedia of Integer Sequences.

132 questions
Filter by
Sorted by
Tagged with
55 views

### Proof of the remarkable formula for the n-th non-square?

The OEIS's A000037 entry makes the remarkable claim that every non-square number is given by the sequence $$a(n) = n + \Big\lfloor \frac 12 + \sqrt n\Big\rfloor$$ After looking through the entry, I ...
32 views

### On Hypergeometric Series and OEIS Sequence

I have been searching an integer sequence in OEIS. The sequence is the following: OEIS A321234 (https://oeis.org/A321234) . So far, so good. However, this sequence is the denominator of a ...
26 views

### Is there any website like OEIS for special polynomials

I would like to know if there is any kind of website (like OEIS) in which we can search for special known polynomials. For example, we put the coefficients of Legendre's and then the website gives us ...
95 views

### Explicit closed formulas for A056542 and A079751?

Consider the recurrence $B_1 = 0$, $B_n = nB_{n-1} + 1$ for $n\ge 1$ as defined by http://oeis.org/A056542 or by R. Sedgewick, Permutation generation methods, Computing Surveys, 9 (1977), 137–164. How ...
68 views

### Why this rational approximation $\pi\sim\frac{80249}{25544}$ is not mentioned in OEIS?

I have checked sequence of Denominator of best approximation to $\pi$ with denominator $\le10^n$ in OEIS but I didn't find this rational $\frac{80249}{25544}$ however it is better than $\frac{22}7$, ...