A096842 Sigma applied to A096841 produces these repdigits: a[n]=A000203[A096841(n)].

1, 3, 4, 7, 6, 8, 44, 222, 444, 888, 444, 888, 888, 2222, 6666, 8888, 8888, 222222, 88888, 222222, 444444, 444444, 888888, 444444, 444444, 666666, 888888, 888888, 888888, 888888, 888888, 444444, 444444, 888888, 888888, 888888, 888888, 888888

Offset

1,2

Links

Table of n, a(n) for n=1..38.

Example

n=43:sigma[43]=44;

Mathematica

rd[x_] := Length[Union[IntegerDigits[x]]] Do[s = rd[DivisorSigma[1, n]]; s1 = DivisorSigma[1, n]; If[Equal[s, 1], Print[{n, s1}]; ta[[u]] = n; u = u + 1], {n, 1, 1000000}]; ta; DivisorSigma[1, ta]

Crossrefs

Cf. A096503-A096508, A096841-A096846, A000203.

Sequence in context: A204823 A211657 A215430 * A147966 A351923 A341944

Adjacent sequences: A096839 A096840 A096841 * A096843 A096844 A096845

Keyword

base,nonn

Author

Labos Elemer, Jul 15 2004

Status

approved