A277650 Numbers with primitive English number names.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 30, 40, 50

Offset

1,3

Comments

A "primitive English number name" is defined here as an English number name whose letters do not fully spell any other English number name.

English number names for all numbers not in this sequence consist of letters that spell at least one of these words: zero, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirty, forty, fifty. If "zero" is removed from this list, the statement is still true. Any further removals depend upon whether names such as the British "milliard" are permitted; e.g., "eleven milliard" requires "eleven" to stay in the list (lack of a second "n" does not permit "nine" here).

Links

Table of n, a(n) for n=1..16.

Example

The number 13 is not a term because "three" or "ten" can be spelled using the letters in "thirteen". On the other hand, 50 is a term because the letters in "fifty" cannot be used to form any other English number name.

Crossrefs

Cf. A005589 (see many English number names).

Sequence in context: A243020 A061921 A342042 * A341090 A071786 A151766

Adjacent sequences: A277647 A277648 A277649 * A277651 A277652 A277653

Keyword

nonn,word,fini,full

Author

Rick L. Shepherd, Oct 25 2016

Status

approved