

A030455


Numbers having the same number of digits as letters in their US English spelling.


1



1000000000, 2000000000, 6000000000, 3000000000000, 7000000000000, 8000000000000, 10000000000001, 10000000000002, 10000000000006, 10000000000010, 11000000000000, 12000000000000, 20000000000000, 30000000000000, 80000000000000, 90000000000000, 3000000000000000
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OFFSET

1,1


COMMENTS

Or, numbers N such that A005589(N)=A055642(N).


LINKS

Table of n, a(n) for n=1..17.
Wiktionary, One hundred one.
L. C. Noll, The English name of a number.


EXAMPLE

"One billion" has 10 letters and "1000000000" has 10 digits.
a(7)=10^13+1 (ten trillion one) has 14 digits and also 14 letters in the US English spelling (while the preferred British spelling is "...and one"). The same applies to a(8)=10^13+2, a(9)=10^13+6, a(10)=10^13+10, a(11)=11*10^12, a(12)=12*10^12, a(13)=20*10^12, a(14)=30*10^12, a(15)=80*10^12, a(16)=90*10^12.  M. F. Hasler, Feb 13 2012


PROG

(PARI) {N=1; while(1, while(0>d=#Str(N*=10)A005589(N), );
d  for(k=1, 3, print1(k!*N", "))  next; for(k=1, 90, for(u=0, 90, A005589(k*N+u)==#Str(k*N) & print1(k*N+u", "))))}


CROSSREFS

See A204593 for the French version.
Sequence in context: A260519 A260520 A033423 * A250600 A250864 A017181
Adjacent sequences: A030452 A030453 A030454 * A030456 A030457 A030458


KEYWORD

nonn,word,base


AUTHOR

Dann Toliver, 1999


EXTENSIONS

Corrected by M. F. Hasler, Feb 13 2012


STATUS

approved



