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Index of n in A125718, or 0 if n does not occur; A125718(k) = least number congruent to prime(k) (mod k) and not occurring earlier.
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%I #17 Jan 15 2024 01:43:37

%S 1,3,2,75,9,5,4,17,10,7,8,91,6,23,13,83,15,16049,43,11,16,25,26,95,12,

%T 449,452,99,14,451,20,453,1072,31,22,16043,34,33,56,459,24,101,18,35,

%U 62,37,102,19,27,39,28,21,30,109,42,41,118,117,120,487,44,45,67

%N Index of n in A125718, or 0 if n does not occur; A125718(k) = least number congruent to prime(k) (mod k) and not occurring earlier.

%C If A125718 is a permutation of the positive integers, then this is the inverse permutation.

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%o (PARI) A249678(n)=for(i=1,9e9,A125718(i)==n&&return(i))

%K nonn

%O 1,2

%A _M. F. Hasler_, Nov 03 2014