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.

A360407 Irregular table T(n, k), n >= 0, k = 0..A002110(n)-1, read by rows; for any k with primorial base expansion (d_n, ..., d_1), T(n, k) is the least number t such that t mod prime(u) = d_u for u = 1..n (where prime(u) denotes the u-th prime number).

Original entry on oeis.org

0, 0, 1, 0, 3, 4, 1, 2, 5, 0, 15, 10, 25, 20, 5, 6, 21, 16, 1, 26, 11, 12, 27, 22, 7, 2, 17, 18, 3, 28, 13, 8, 23, 24, 9, 4, 19, 14, 29, 0, 105, 70, 175, 140, 35, 126, 21, 196, 91, 56, 161, 42, 147, 112, 7, 182, 77, 168, 63, 28, 133, 98, 203, 84, 189, 154, 49
Offset: 0

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Author

Rémy Sigrist, Feb 06 2023

Keywords

Comments

When computing T(n, k), we pad the primorial base expansion of k with leading zeros so as to have n digits.
The Chinese remainder theorem ensures that this sequence is well defined and provides a way to compute it.
The n-th row is a permutation of 0..A002110(n)-1.

Examples

			Table T(n, k) begins:
    0;
    0, 1;
    0, 3, 4, 1, 2, 5;
    0, 15, 10, 25, 20, 5, 6, 21, 16, 1, 26, 11, 12, 27, 22,
                  7, 2, 17, 18, 3, 28, 13, 8, 23, 24, 9, 4, 19, 14, 29;
    ...
		

Crossrefs

See A343404 for a similar sequence.

Programs

  • PARI
    T(n,k) = { my (t=Mod(0,1)); if (n, forprime (p=2, prime(n), t=chinese(t, Mod(k, p)); k\=p)); lift(t) }

Formula

T(n, 0) = 0.
T(n, 1) = A070826(n) for any n > 0.
T(n, A002110(n) - 1) = A057588(n) for any n > 0.
T(n, k) + T(n, A002110(n) - 1 - k) = A002110(n) - 1.