A284063 Numbers whose smallest decimal digit is 2.

2, 22, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, 92, 222, 223, 224, 225, 226, 227, 228, 229, 232, 233, 234, 235, 236, 237, 238, 239, 242, 243, 244, 245, 246, 247, 248, 249, 252, 253, 254, 255, 256, 257, 258, 259, 262, 263, 264, 265, 266, 267, 268

Offset: 1

Author

Jaroslav Krizek, Mar 19 2017

Keywords

• nonn
• base

Comments

Numbers n such that A054054(n) = 2.

Prime terms are in A106102.

Crossrefs

Cf. Sequences of numbers whose smallest decimal digit is k (for k = 0..9): A011540 (k = 0), A284062 (k = 1), this sequence (k = 2), A284064 (k = 3), A284065 (k = 4), A284066 (k = 5), A284067 (k = 6), A284068 (k = 7), A284069 (k = 8), A002283 (k = 9).

Programs

Magma

[n: n in [1..100000] | Minimum(Setseq(Set(Sort(&cat[Intseq(n)])))) eq 2]

Mathematica

Select[Range[300], Min[IntegerDigits[#]] == 2 &] (* Alonso del Arte, Mar 19 2017 *)

PARI

isok(n) = vecmin(digits(n)) == 2; \\ Michel Marcus, Mar 25 2017

Python

def ok(n): return '2' == min(str(n))
print([m for m in range(269) if ok(m)]) # Michael S. Branicky, Feb 22 2021