A098934 Numbers n such that the sum of the first n digits of Pi are divisible by n.

1, 2, 9, 11, 16

Offset: 1

Author

Anne M. Donovan (anned3005(AT)aol.com), Oct 20 2004

Keywords

• base
• easy
• fini
• full
• nonn
• changed

Comments

For large n, A046974(n-1)/n is very close to 4.5, so is never an integer. - David Wasserman, Feb 27 2008

Examples

			a[1] = 1 since 3 is divisible by 1.
a[2] = 2 since 3 + 1 = 4 is divisible by 2.
a[3] != 3 since 3 + 1 + 4 = 8 is not divisible by 3.
		

Crossrefs

Cf. A046974.

Programs

Mathematica

$MaxPrecision = 2500000; pd = RealDigits[N[Pi, 2000000]][[1]]; s = 0; Do[s = s + pd[[n]]; If[ Mod[s, n] == 0, Print[n]], {n, 2000000}] (* Robert G. Wilson v, Oct 21 2004 *)
Module[{nn=20,pid},pid=RealDigits[Pi,10,nn][[1]];Select[Range[nn],Mod[Total[Take[pid,#]],#]==0&]] (* Harvey P. Dale, Aug 30 2025 *)