A089284 Number of divisors of floor(Pi*10^n), Pi=3.14...

2, 2, 4, 6, 8, 2, 8, 8, 48, 8, 16, 4, 8, 8, 8, 8, 72, 4, 64, 96, 16, 64, 128, 128, 8, 24, 256, 8, 32, 64, 16, 64, 192, 4, 24, 40, 96, 2, 32, 4, 16, 48, 8, 32, 16, 64, 48, 8, 320, 8, 32, 48, 8, 64, 192, 48, 16, 32, 16, 64, 96, 128, 8, 120, 16, 64, 32, 48, 8, 32, 192, 512, 64, 96, 144

Offset: 0

Author

Reinhard Zumkeller, Oct 30 2003

Keywords

• nonn

Examples

			For n=4: floor(Pi*10^4)=31415 has divisors: 1,5,61,103,305,515,6283,31415; a(4)=8.
		

Links

• Tyler Busby, Table of n, a(n) for n = 0..200
• Dario Alejandro Alpern, Factorization using the Elliptic Curve Method.
• Hisanori Mishima, Decimal expansions of pi (n = 0 to 100, n = 101 to 200, n = 201 to 250).

Crossrefs

Cf. A089282, A089283, A000796.

Programs

Mathematica

Table[ DivisorSigma[ 0, Floor[ Pi*10^n]], {n, 0, 10}] (* Robert G. Wilson v, Oct 30 2003 *)

PARI

A089284(n)=numdiv(Pi\.1^n)  \\ M. F. Hasler, Nov 01 2012

Formula

a(n) = A000005(A011545(n)).

Extensions

More terms from Robert G. Wilson v and Ray Chandler, Oct 30 2003