A117113 Number of letters not in common with the number before.

1, 2, 4, 3, 3, 2, 4, 4, 2, 1, 4, 2, 5, 3, 2, 2, 4, 3, 2, 3, 3, 2, 4, 3, 3, 2, 4, 4, 2, 2, 3, 2, 4, 3, 3, 2, 4, 4, 2, 2, 3, 2, 4, 3, 3, 2, 4, 4, 2, 1, 3, 2, 4, 3, 3, 2, 4, 4, 2, 2, 3, 2, 4, 3, 3, 2, 4, 4, 2, 2, 3, 2, 4, 3, 3, 2, 4, 4, 2, 2, 3, 2, 4, 3, 3, 2, 4, 4

Offset

1,2

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Example

a(1)=1 from oNe & zErO, a(2)=2 from TWo & One, a(3)=4 from tHREE & Two, a(8)=4 from eIGHT & sEven, etc.
a(20)=3 from tWenTY & nineTEeN.

Prog

(Python)
from collections import Counter
from num2words import num2words
def n2w(n): return "".join(c for c in num2words(n).replace(" and", "") if c.isalpha())
def a(n): return (Counter(n2w(n)) - Counter(n2w(n-1))).total()
print([a(n) for n in range(1, 103)]) # Michael S. Branicky, Jan 13 2026

Crossrefs

Cf. A005589, A109382, A116531.

Sequence in context: A244646 A308182 A220080 * A343766 A299920 A384436

Adjacent sequences: A117110 A117111 A117112 * A117114 A117115 A117116

Keyword

nonn,word

Author

Rodolfo Kurchan, Apr 18 2006

Extensions

Offset, a(1) and a(20) corrected and a(24) onward from Michael S. Branicky, Jan 13 2026

Status

approved