A284065 Numbers whose smallest decimal digit is 4.

4, 44, 45, 46, 47, 48, 49, 54, 64, 74, 84, 94, 444, 445, 446, 447, 448, 449, 454, 455, 456, 457, 458, 459, 464, 465, 466, 467, 468, 469, 474, 475, 476, 477, 478, 479, 484, 485, 486, 487, 488, 489, 494, 495, 496, 497, 498, 499, 544, 545, 546, 547, 548, 549, 554

Offset: 1

Author

Jaroslav Krizek, Mar 19 2017

Keywords

• nonn
• base

Comments

Numbers n such that A054054(n) = 4.

Prime terms are in A106104.

Crossrefs

Cf. Sequences of numbers whose smallest decimal digit is k (for k = 0..9): A011540 (k = 0), A284062 (k = 1), A284063 (k = 2), A284064 (k = 3), this sequence (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 4]

Mathematica

With[{k = 4}, Select[Range@ 554, And[Total@ Take[#, k] == 0, #[[k + 1]] > 0] &@ RotateRight@ DigitCount@ # &]] (* Michael De Vlieger, Mar 20 2017 *)
(* or *)
Select[Range[1000], Min[IntegerDigits[#]] == 4 &] (* Giovanni Resta, Mar 22 2017 *)

PARI

isok(n) = vecmin(digits(n)) == 4; \\ Michel Marcus, Mar 25 2017