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.

Showing 1-2 of 2 results.

A002956 Number of basic invariants for cyclic group of order and degree n.

Original entry on oeis.org

1, 2, 4, 7, 15, 20, 48, 65, 119, 166, 348, 367, 827, 974, 1494, 2135, 3913, 4038, 7936, 8247, 12967, 17476, 29162, 28065, 49609, 59358, 83420, 97243, 164967, 152548, 280352, 295291, 405919, 508162, 674630, 708819, 1230259, 1325732, 1709230
Offset: 1

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Keywords

Comments

a(n) is also the number of multisets of integers ranging from 1 to n, such that the sum of the members of the multiset is congruent to 0 mod n, and no submultiset exists whose sum of members is congruent to 0 mod n. These multisets can be thought of as partitions of n in modular arithmetic, thus this sequence can be thought of as a modular arithmetic version of the partition numbers (cf. A000041). - Andrew Weimholt, Jan 31 2011

References

  • M. D. Neusel and L. Smith, Invariant Theory of Finite Groups, Amer. Math. Soc., 2002; see p. 208.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • C. W. Strom, Complete systems of invariants of the cyclic groups of equal order and degree, Proc. Iowa Acad. Sci., 55 (1948), 287-290.

Crossrefs

Row sums of A082641.
Cf. A096337.

Formula

a(n) = A096337(n) + 1. - Filip Zaludek, Oct 26 2016

Extensions

More terms from Vadim Ponomarenko (vadim123(AT)gmail.com), Jun 29 2004

A296303 Number of minimal nonnegative nonzero solutions of the linear Diophantine equation x_1 + 2*x_2 + ... + n*x_n = y_1 + 2*y_2 + ... + n*y_n.

Original entry on oeis.org

1, 4, 13, 34, 99, 210, 559, 1164, 2531, 4940, 10735
Offset: 1

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Author

Klaus Pommerening, Dec 10 2017

Keywords

Comments

Every linear Diophantine equation with arbitrary integer coefficients may be reduced to this one.
The minimal nonnegative nonzero solutions form a generating system of the semigroup of all nonnegative solutions.
The asymptotic behavior of a(n) is unknown, it is somewhere between a*exp(b*sqrt(n))/(sqrt(n)) and c*exp(d*n)/n with positive real numbers a,b,c,d.
A096337 contains the number of minimal nonnegative nonzero solutions of the linear congruence x_1 + 2 x_2 + ... + (n-1) x_{n-1} == 0 (mod n). There is an obvious relation with a(n) since every solution (x_1, ..., x_{n-1}) of the linear congruence yields a solution (x_1, ..., x_{n-1}; 0, 0, ..., 0, k) of the linear Diophantine equation.

Examples

			The 13 minimal solutions for n=3 are (x-coordinates followed by y-coordinates): (0,0,1;0,0,1), (0,0,1;1,1,0), (0,0,1;3,0,0), (0,0,2;0,3,0), (0,1,0;0,1,0), (0,1,0;2,0,0), (0,2,0;1,0,1), (0,3,0;0,0,2), (1,0,0;1,0,0), (1,0,1;0,2,0), (1,1,0;0,0,1), (2,0,0;0,1,0), (3,0,0;0,0,1).
		

Crossrefs

Programs

  • Python
    See Pommerening link.

Formula

Lower and upper bounds (proved) are a(n) >= 2*A026905(n) for n >= 3 and a(n) <= A002894(n-1).
Showing 1-2 of 2 results.