A276480 a(n) = the smallest number k such that floor(Sum_{d|k} 0.d) = n.

1, 6, 18, 36, 72, 120, 168, 288, 420, 360, 792, 720, 1512, 1260, 1440, 3240, 4032, 2880, 2520, 3960, 5544, 6720, 5040, 10920, 7560, 14400, 10080, 13860, 15840, 15120, 18480, 20160, 37440, 25200, 46800, 30240, 36960, 32760, 27720, 71280, 50400, 69300, 60480

Offset

0,2

Comments

Here 0.d means the decimal fraction obtained by writing d after the decimal point, e.g., 0.12 = 12/100 = 3/25.

a(n) = the smallest number k such that floor (A276466(k)/A276467(k)) = n.

The first few values of Sum_{d|n} 0.d are 1/10, 3/10, 2/5, 7/10, 3/5, 6/5, 4/5, 3/2, 13/10, 9/10, 21/100, 43/25, ...

Links

Chai Wah Wu, Table of n, a(n) for n = 0..477

Mathematica

Table[k = 1; While[Floor@ Total@ (#*1/10^(1 + Floor@ Log10@ #)) != n &@ Divisors@ k, k++]; k, {n, 0, 40}] (* Michael De Vlieger, Sep 06 2016 *)

Prog

A276480:=func<n|exists(r){k:k in[1..100000] | Floor(&+[d / (10^(#Intseq(d))): d in Divisors(k)]) eq n}select r else 0>; [A276480(n): n in[0..45]]
(PARI) a(n) = {k = 1; while(floor(sumdiv(k, d, d/10^(#Str(d)))) != n, k++); k; } \\ Michel Marcus, Sep 05 2016

Crossrefs

Cf. A276466, A276467, A276479.

Sequence in context: A372847 A116367 A225384 * A180438 A202366 A185223

Adjacent sequences: A276477 A276478 A276479 * A276481 A276482 A276483

Keyword

nonn,base

Author

Jaroslav Krizek, Sep 05 2016

Status

approved