1,1

a(1) is 3 because UNO has 3 letters by 1 = 3, a(2) is 6 because DOS has 3 letters by 2 = 6, a(3) is 12 because TRES has 4 letters by 3 = 12, a(4) is 24 because CUATRO has 6 letters by 4 = 24, a(5) is 25 because CINCO has 5 letters by 5 = 25.

Published in Snark, Feb 27 2001

Table of n, a(n) for n=1..15.

Sequence in context: A005256 A097979 A215983 * A003204 A038620 A039695

Adjacent sequences: A173213 A173214 A173215 * A173217 A173218 A173219

nonn,word

Rodolfo Kurchan, Feb 12 2010

approved