OFFSET
1,2
COMMENTS
Assumes the American usage of billion, trillion, etc. ("short scale"), which makes a difference from a(59) on.
See A002810 for the British English version, which in particular includes the additional "and", e.g., in "one hundred and seven". Therefore the sequences differ from a(6)=111 on, with A002810(6)= 107. - M. F. Hasler, Nov 03 2013
LINKS
FORMULA
a(n) = min{ k | A075774(k)=n }. - M. F. Hasler, Nov 03 2013
a(n+11) = a(n)*1000+777, as long as a(n+11) is less than one quadrillion (whatever scale is used). - M. F. Hasler, Nov 03 2013
PROG
(PARI) A045736(n)={n>11 || for(k=1, 1e5, A075774(k)==n && return(k)); A045736(n-11*n=(n-1)\11)*1000^n+1000^n\9*7 } \\ This code is valid up to n=58 (short scale) or n=82 (long scale). - M. F. Hasler, Nov 03 2013
CROSSREFS
KEYWORD
nonn,word
AUTHOR
STATUS
approved