A208262 Numbers with all divisors starting and ending with digit 1.

1, 11, 101, 121, 131, 151, 181, 191, 1021, 1031, 1051, 1061, 1091, 1111, 1151, 1171, 1181, 1201, 1231, 1291, 1301, 1321, 1331, 1361, 1381, 1441, 1451, 1471, 1481, 1511, 1531, 1571, 1601, 1621, 1661, 1721, 1741, 1801, 1811, 1831, 1861, 1871, 1901, 1931, 1951, 1991

Offset

1,2

Comments

Union of A062332 and A208261. Subsequence of A208259 (numbers starting and ending with digit 1).

Links

Table of n, a(n) for n=1..46.

Example

Divisors of 1111: 1, 11, 101, 1111.

Mathematica

Select[Table[n, {n, 2000}], Union[First /@ IntegerDigits[Divisors[#]]] == {1} && Union[Last /@ IntegerDigits[Divisors[#]]] == {1} &] (* Vladimir Joseph Stephan Orlovsky, Feb 26 2012 *)

Crossrefs

Cf. A062332 (primes starting and ending with digit 1), A208261 (nonprime numbers with all divisors starting and ending with digit 1).

Sequence in context: A176179 A176196 A303570 * A062696 A113654 A066592

Adjacent sequences: A208259 A208260 A208261 * A208263 A208264 A208265

Keyword

nonn,base

Author

Jaroslav Krizek, Feb 24 2012

Status

approved