A030455 Numbers having the same number of digits as letters in their US English spelling.

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

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..17.

L. C. Noll, The English name of a number.

Wiktionary, One hundred one.

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