A159451 Number of numbers less than n, that are contained in n written as English number names.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 3, 3, 3, 3, 3, 2, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 2, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 2, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 2, 1, 2, 3, 3, 3

Offset

0,22

Comments

a(A159452(n)) = 0;

a(A159453(n)) = n and a(m) <> n for m < A159453(n).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Robert G. Wilson v, English names for the numbers from 0 to 11159 without spaces or hyphens

Example

n = 19 -> nineteen:  a(19) = #{nine} = 1;
n = 20 -> twenty:    a(20) = #{} = 0;
n = 21 -> twentyone: a(21) = #{one, twenty} = 2.

Prog

(Python)
from num2words import num2words
from functools import cache
@cache
def n2w(n):
    map = {ord(c): None for c in "-, "}
    return num2words(n).replace(" and", "").translate(map)
def a(n): wn = n2w(n); return sum(1 for i in range(n) if n2w(i) in wn)
print([a(n) for n in range(105)]) # Michael S. Branicky, Feb 13 2024

Crossrefs

Cf. A000027, A159452, A159453.

Sequence in context: A055178 A174847 A215887 * A336682 A103159 A063056

Adjacent sequences: A159448 A159449 A159450 * A159452 A159453 A159454

Keyword

nonn,word

Author

Reinhard Zumkeller, Apr 12 2009

Status

approved