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.

A073162 n is such that partial sum of pi(k) from 1 to n is divisible by n.

Original entry on oeis.org

1, 3, 17, 37, 9107, 156335, 679083, 1068131, 4883039, 101691357
Offset: 1

Views

Author

Labos Elemer, Jul 18 2002

Keywords

Comments

a(11) > 10^12. - Donovan Johnson, Mar 19 2011
a(11) > 10^13. - Lucas A. Brown, Oct 05 2020

Examples

			a(3) = 17 because 0+1+2+2+3+3+4+4+4+4+5+5+6+6+6+6+7 = 68 = 4*17.
		

Crossrefs

Programs

  • Mathematica
    s = 0; Do[s = s + PrimePi[n]; If[ IntegerQ[s/n], Print[{n, s, s/n}]], {n, 1, 10^8}]
    Module[{nn=11 10^5,pspi},pspi=Accumulate[PrimePi[Range[nn]]];Select[Thread[{Range[nn],pspi}],Mod[#[[2]],#[[1]]]==0&]][[;;,1]] (* The program generates the first 8 terms of the siequence. *) (* Harvey P. Dale, Mar 19 2025 *)

Formula

Solutions to Mod[A046992(x), x]=0

Extensions

Edited and extended by Robert G. Wilson v, Jul 20 2002
a(10) from Donovan Johnson, Dec 15 2009

A073163 Partial sums of Pi(k) arising in A073162.

Original entry on oeis.org

0, 3, 68, 259, 5500628, 1180641920, 19503263760, 46464766631, 863653341852, 306757978180563
Offset: 1

Views

Author

Labos Elemer, Jul 18 2002

Keywords

Examples

			Sum of first 17 values of Pi(n) equals 0+1+2+2+3+3+4+4+4+4+5+5+6+6+6+6+7 = 68 = 4*17. To continue, see A073224.
		

Crossrefs

Programs

  • Mathematica
    s = 0; Do[s = s + PrimePi[n]; If[ IntegerQ[s/n], Print[{n, s, s/n}]], {n, 1, 10^8}]

Formula

Values of s(n) = A046992(n) such that s(n)/n is an integer.

Extensions

Edited and extended by Robert G. Wilson v, Jul 20 2002
a(10) from Donovan Johnson, Dec 15 2009
Showing 1-2 of 2 results.