A257220 Numbers that have at least one divisor containing the digit 3 in base 10.

3, 6, 9, 12, 13, 15, 18, 21, 23, 24, 26, 27, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 42, 43, 45, 46, 48, 51, 52, 53, 54, 57, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 73, 74, 75, 76, 78, 81, 83, 84, 86, 87, 90, 91, 92, 93, 96, 99, 102, 103, 104, 105, 106, 108

Offset

1,1

Comments

Numbers k whose concatenation of divisors A037278(k), A176558(k), A243360(k) or A256824(k) contains a digit 3.

Sequences of numbers k whose concatenation of divisors contains a digit j in base 10 for 0 <= j <= 9: A209932 for j = 0, A000027 for j = 1, A257219 for j = 2, A257220 for j = 3, A257221 for j = 4, A257222 for j = 5, A257223 for j = 6, A257224 for j = 7, A257225 for j = 8, A257226 for j = 9.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ n. - Charles R Greathouse IV, Apr 30 2015

Example

18 is in sequence because the list of divisors of 18: (1, 2, 3, 6, 9, 18) contains digit 3.

Mathematica

Select[Range@108, Part[Plus @@ DigitCount@ Divisors@ #, 3] > 0 &] (* Michael De Vlieger, Apr 20 2015 *)

Prog

(Magma) [n: n in [1..1000] | [3] subset Setseq(Set(Sort(&cat[Intseq(d): d in Divisors(n)])))]
(PARI) is(n)=fordiv(n, d, if(setsearch(Set(digits(d)), 3), return(1))); 0 \\ Charles R Greathouse IV, Apr 30 2015

Crossrefs

Cf. A037278, A176558, A243360, A256824.

Sequence in context: A285402 A153403 A336341 * A092452 A230215 A120688

Adjacent sequences: A257217 A257218 A257219 * A257221 A257222 A257223

Keyword

nonn,base

Author

Jaroslav Krizek, Apr 20 2015

Status

approved