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%I #16 May 25 2019 11:57:45
%S 3,5,8,9,14,17,23,25,28,33,35,38,43,45,48,53,55,58,63,65,68,73,75,78,
%T 83,85,88,93,95,98,103,105,108,109,114,117,123,125,128,133,135,138,
%U 143,145,148,153,155,158,163,165,168,173,175,178,183,185,188,193,195
%N Numbers k such that k, when written in English, has 1 letter more than k+1.
%e a(1) = 3 = THREE has 1 letter more than a(1) + 1 = FOUR;
%e a(2) = 5 = FIVE has 1 letter more than a(2) + 1 = SIX;
%e a(3) = 8 = EIGHT has 1 letter more than a(3) + 1 = NINE;
%e a(4) = 9 = NINE has 1 letter more than a(4) + 1 = TEN;
%e a(5) = 14 = FOURTEEN has 1 letter more than a(5) + 1 = FIFTEEN; etc.
%o (PARI) v1 = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
%o v2 = ["eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"];
%o v3 = ["ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"];
%o conv(n) = {if (n >= 10^12, error("too big for this program"));
%o if (n >= 10^9, return (concat(concat(conv(n\10^6), "billion"), conv(n % 10^9))));
%o if (n >= 10^6, return (concat(concat(conv(n\10^6), "million"), conv(n % 10^6))));
%o if (n >= 10^3, return (concat(concat(conv(n\10^3), "thousand"), conv(n % 10^3))));
%o if (n >= 10^2, return (concat(concat(conv(n\100), "hundred"), conv(n % 100))));
%o if (n >= 20, return (concat(v3[n\10], conv(n%10))); );
%o if (n >= 10, if (n==10, return(v3[n\10]), return(v2[n % 10])); );
%o if (n, return(v1[n]), return (""));
%o } \\ after _Michel Marcus_ in A303475
%o is(n) = #conv(n)-1==#conv(n+1) \\ _Felix Fröhlich_, May 25 2019
%K nonn,word
%O 1,1
%A _Eric Angelini_, May 25 2019
%E 17 and terms beyond 98 from _Felix Fröhlich_, May 25 2019
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