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.

A181486 Record values in A171919 = number of solutions to n=x*y*z, x+y=z+1.

Original entry on oeis.org

1, 2, 3, 6, 8, 10, 14, 16, 20, 22, 24, 26, 28, 34, 38
Offset: 1

Views

Author

R. J. Mathar and M. F. Hasler, Oct 23 2010

Keywords

Comments

The sequence lists all m=A171919(n) such that m > A171919(k) for all k < n.
The indices n for which these record values are taken are given in A181485.
Larger numbers of solutions do occur, for example A171919(388778796252000) = 38 (although this may not even be a record). - Georgi Guninski, Jan 04 2011

Crossrefs

Cf. A171919, A181485.

Programs

  • PARI
    m=0; for(n=1,1e9, A171919(n)>m | next; print1(m=A171919(n),", "))

Formula

A181486(n) = A171919(A181485(n)).

Extensions

a(10)-a(13) from Donovan Johnson, Jun 14 2011
a(14)-a(15) from Robert Gerbicz, Apr 10 2012

A181485 Indices of records in A171919 = number of solutions to n=x*y*z, x+y=z+1.

Original entry on oeis.org

1, 4, 112, 144, 23400, 28224, 247104, 604800, 26812800, 2677752000, 6805814400, 165145780800, 1248124550400, 17996854730400, 388778796252000
Offset: 1

Views

Author

R. J. Mathar and M. F. Hasler, Oct 23 2010

Keywords

Comments

The sequence lists all n such that A171919(n) > A171919(k) for all k < n.
Also the subsequence of terms of A171920 for which A171919 is larger than for all preceding values.
The actual record values are given in A181486.
a(10) > 5*10^7.
It seems highly probable that all terms of this sequence, except for a(1) = 1, are multiples of 4.
a(14) > 4*10^12. - Donovan Johnson, Jun 14 2011
a(16) > 2*10^17. - Robert Gerbicz, Apr 10 2012

Examples

			a(1) = 1 since there is no smaller value possible.
a(2) = 4 is the smallest number for which there are more than 1 = A171919(1) solutions to n = x*y*z, x + y = z + 1.
a(3) = 112 is the smallest number for which there are more than 2 = A171919(4) solutions to n = x*y*z, x + y = z + 1.

Programs

  • PARI
    m=0;for(n=1,1e9,A171919(n)>m | next; m=A171919(n); print1(n", "))

Extensions

a(10)-a(13) from Donovan Johnson, Jun 14 2011
a(14)-a(15) from Robert Gerbicz, Apr 10 2012
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.