A221697 -id:A221697 - cp's OEIS frontend

A106100 Primes with maximal digit = 2.

2, 211, 1021, 1201, 2011, 2111, 2221, 10211, 12011, 12101, 12211, 20011, 20021, 20101, 20201, 21001, 21011, 21101, 21121, 21211, 21221, 22111, 101021, 101221, 102001, 102101, 102121, 110221, 111121, 111211, 112111, 112121, 120011, 120121

Offset: 1

Zak Seidov, May 07 2005

Subsequence of A036953. Prime numbers p such that A209928(p) = 2. Complement of A221698 with respect to A221697. [Jaroslav Krizek, Jan 22 2013]

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A106093, A106094, A106095, A106096, A106097, A106098, A106099.

N:= 6: # to get all terms of up to N digits
M2:= {1};M1:= {1}:
for d from 1 to N-1 do
  M2:= map(t -> (t, t+10^d, t+2*10^d), M2);
  M1:= map(t -> (t, t+10^d), M1);
od:
sort(convert({2} union select(isprime,M2 minus M1),list)); # Robert Israel, Jun 19 2016

Select[Prime[Range[10000]], Max[IntegerDigits[ # ]]==2&]

isok(p) = isprime(p) && (vecmax(digits(p)) == 2); \\ Michel Marcus, Jan 02 2019

More terms from Rick L. Shepherd, May 22 2005

A221698 Composite numbers n such that largest digit of all divisors of n is 2.

Original entry on oeis.org

22, 121, 202, 1111, 2222, 10201, 12221, 20222, 22121, 111221, 112211, 202222, 220121, 221111, 222211, 1021211, 1112221, 1122011, 1222201, 2021111, 2022002, 2022121, 2121101, 2122111, 2200202, 2202211, 2211121, 2212111, 2222011, 10212211, 11112211, 11121011

Offset: 1

Jaroslav Krizek, Jan 22 2013

Also composite numbers n such that largest digit of concatenation of all divisors (A037278) of n is 2.
Composite numbers n such that A209928(n) = 2.
Complement of A106100 with respect to A221697.

			Number 10201 is in the sequence because the largest digit of all divisors of 10201 (1, 101, 10201) is 2.

Cf. A209928 (largest digit of all divisors of n), A221697.

t = {}; n = 1; While[Length[t] < 40, n++; m = FromDigits[IntegerDigits[n, 3]]; If[! PrimeQ[m] && Max[Union[Flatten[IntegerDigits[Divisors[m]]]]] <= 2, AppendTo[t, m]]]; t (* T. D. Noe, Jan 30 2013 *)

cp's OEIS Frontend

A106100 Primes with maximal digit = 2.

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