login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

First occurrence of n in A111633.
1

%I #4 Dec 05 2013 19:57:05

%S 1,11,13,14,15,16,17,18,19,25,205,1139,1149,1159,26,206,1189,1199,

%T 1259,36,27,207,1268,1269,1274,1275,1276,28,208,1279,1283,1284,1285,

%U 1286,37,29,209,1291,1293,1294,1295,1296,1297,1298,1299,2259,22059,2368,2278

%N First occurrence of n in A111633.

%C A111633: Let n = abc... denote the decimal digits of n. Then a(n) = C(a,z)+C(b,y)+C(c,x)+...+C(x,c)+C(y,b)+C(z,a).

%t f[n_] := Plus @@ Binomial[ IntegerDigits[n], Reverse[ IntegerDigits[ n]]]; Table[ f[n], {n, 0, 100}]; g[n_] := Block[{k = 1}, While[f[k] != n, k++ ]; k]; Table[ g[n], {n, 50}]

%Y Cf. A111633, A111696.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_ and _Robert G. Wilson v_, Aug 19 2005