A217395 - OEIS (original) (raw)

3, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342

COMMENTS

The lower and upper asymptotic densities of this sequence are 1/27 and 5/18, respectively. - Amiram Eldar, Feb 27 2021

MATHEMATICA

Select[Range[1000], IntegerDigits[#][[1]] == 3 &] (* T. D. Noe, Oct 02 2012 *)

PROG

(Python)

def agen():

yield 3

digits, adder = 1, 30

while True:

for i in range(10**digits): yield adder + i

digits, adder = digits+1, adder*10

g = agen()

(Python)

def A217395(n): return n+26*10**(len(str(9*n-8))-1)//9 # Chai Wah Wu, Sep 11 2024

(PARI) a(n) = n + 26*10^logint(9*n, 10)\9; \\ Kevin Ryde, Mar 30 2021