A301408 Repeatedly map numbers to the number of letters in the English name (include spaces, but no hyphens and no "and"s); sequence gives smallest nonnegative integer that needs exactly n iterations to get to 4.

4, 0, 3, 1, 11, 23, 123, 101323373373

Offset

0,1

References

M. Ecker, Number play, calculators, and card tricks: Mathemagical black holes, in E. Berlekamp and T. Rodgers, eds., The Mathemagician and Pied Puzzler: A Collection in Tribute to Martin Gardner, A. K. Peters, 1999, pp. 41-52.

Links

Table of n, a(n) for n=0..7.

Example

Since "twenty three" has 12 letters (including the space), "twelve" has 6 letters, "three" has 5 letters, "four" has four letters, and no other smaller nonnegative integer maps to 4 in exactly 5 iterations, then a(5) = 23.

Crossrefs

Cf. A227290, A005589, A016037 (these do not count the spaces in the names of larger integers).

Sequence in context: A130801 A280579 A086165 * A227290 A096303 A262695

Adjacent sequences: A301405 A301406 A301407 * A301409 A301410 A301411

Keyword

nonn,word,less

Author

Matthew E. Coppenbarger, Mar 20 2018

Status

approved