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

0,2

Comments

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

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.

Example

0.12345789101112131415161718192021222324252627293031...

Mathematica

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

Prog

(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

Crossrefs

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

Sequence in context: A305077 A302175 A228683 * A371266 A290019 A161924

Adjacent sequences: A133014 A133015 A133016 * A133018 A133019 A133020

Keyword

cons,easy,nonn,base

Author

Omar E. Pol, Oct 20 2007

Status

approved