A217398 Numbers starting with 5.

5, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542

Offset

1,1

Comments

The lower and upper asymptotic densities of this sequence are 1/45 and 5/27, respectively. - Amiram Eldar, Feb 27 2021

Links

Jeremy Gardiner, Table of n, a(n) for n = 1..1111

Index entries for 10-automatic sequences.

Formula

A000030(a(n)) = 5; A143473(a(n)) = a(n). - Reinhard Zumkeller, Mar 13 2014

a(n) = n + (44*10^floor(log_10(9*n-8))-8)/9. - Alan Michael Gómez Calderón, May 17 2023

Mathematica

Select[Range[1000], IntegerDigits[#][[1]] == 5 &] (* T. D. Noe, Oct 02 2012 *)

Prog

(Haskell)
a217398 n = a217398_list !! (n-1)
a217398_list = filter ((== 5) . a000030) [1..]
-- Reinhard Zumkeller, Mar 13 2014
(Python)
def A217398(n): return n+(44*10**(len(str(9*n-8))-1))//9 # Chai Wah Wu, Dec 07 2024

Crossrefs

Cf. A000867, A011535.

Subsequences include: A045711, A077330, A077681, A106415, A106425.

Cf. A131835, A217394, A217395, A217397, A217399, A217400, A217401, A217402.

Sequence in context: A218322 A247707 A082795 * A059008 A218290 A136890

Adjacent sequences: A217395 A217396 A217397 * A217399 A217400 A217401

Keyword

nonn,base,easy

Author

Jeremy Gardiner, Oct 02 2012

Status

approved