A112016 Numbers n with odd length such that sigma(n) = d_1*(d_2^d_3) *...*(d_(k-1)^d_k) where d_1 d_2 ... d_k is the decimal expansion of n.

1, 127, 1443572, 2859151, 5272635, 5469390, 5668072, 9662421, 121734535, 124825592, 161367245, 168215370, 185335291, 211254594, 217299630, 225624553, 236125265, 251716960, 271374710, 272433643, 291732835, 292536521, 345267332

Offset

1,2

Links

Table of n, a(n) for n=1..23.

Example

161367245 is in the sequence because sigma(161367245)=1*(6^1)*(3^6)*(7^2)*(4^5).

Mathematica

Do[h = IntegerDigits[n]; k = Length[h]; If[OddQ[k] && Select[Range[k/2], h[[2# ]] == 0 ==h[[2#+1]] &] == {}&& DivisorSigma[1, n] == h[[1]]*Product[h[[2j]]^h[[2j+1]], {j, k/2}], Print[n]], {n, 162000000}]

Crossrefs

Cf. A112014, A112015.

Sequence in context: A212860 A334668 A135813 * A263165 A135982 A135983

Adjacent sequences: A112013 A112014 A112015 * A112017 A112018 A112019

Keyword

base,nonn

Author

Farideh Firoozbakht, Sep 15 2005

Extensions

a(11)-a(23) from Donovan Johnson, Sep 16 2009

Status

approved