A133017 Decimal expansion of the constant formed by concatenating the imperfect numbers.

1, 2, 3, 4, 5, 7, 8, 9, 1, 0, 1, 1, 1, 2, 1, 3, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 2, 0, 2, 1, 2, 2, 2, 3, 2, 4, 2, 5, 2, 6, 2, 7, 2, 9, 3, 0, 3, 1, 3, 2, 3, 3, 3, 4, 3, 5, 3, 6, 3, 7, 3, 8, 3, 9, 4, 0, 4, 1, 4, 2, 4, 3, 4, 4, 4, 5

Offset: 0

Author

Omar E. Pol, Oct 20 2007

Keywords

• cons
• easy
• nonn
• base

Comments

A theorem of Copeland & Erdős proves that this constant is 10-normal. - Charles R Greathouse IV, Feb 06 2015

Examples

			0.12345789101112131415161718192021222324252627293031...
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000
• A. H. Copeland and P. Erdős, Note on normal numbers, Bull. Amer. Math. Soc. 52 (1946), pp. 857-860.

Crossrefs

Cf. A007376, A033307, A033308, A079718. Imperfect numbers: A132999.

Programs

Mathematica

Flatten[IntegerDigits/@Table[If[PerfectNumberQ[n],Nothing,n],{n,70}]] (* Harvey P. Dale, Dec 16 2021 *)

PARI

print1(1); for(n=2, 45, if(sigma(n,-1)!=2, d=digits(n); for(i=1, #d, print1(", "d[i])))) \\ Charles R Greathouse IV, Feb 06 2015