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%I #16 Mar 31 2023 14:10:18
%S 1,2,6,12,60,420,504,840,2520,27720,360360,720720,4084080
%N Sorted positions of first appearances in A328458 (maximum run-length of nontrivial divisors) of each positive integer in the image.
%e The sequence of terms > 1 together with their nontrivial divisors begins:
%e 2: {}
%e 6: {2,3}
%e 12: {2,3,4,6}
%e 60: {2,3,4,5,6,10,12,15,20,30}
%e 420: {2,3,4,5,6,7,10,12,14,15,20,21,28,30,35,42,60,70,84,105,140,210}
%e 504: {2,3,4,6,7,8,9,12,14,18,21,24,28,36,42,56,63,72,84,126,168,252}
%t dav=Table[Switch[n,1,1,_,Max@@Length/@Split[DeleteCases[Divisors[n],1|n],#2==#1+1&]],{n,1000}];
%t Table[Position[dav,i][[1,1]],{i,Union[dav]}]//Sort
%Y Positions of first appearances in A328458.
%Y The version for all divisors is A051451.
%Y Cf. A000005, A033676, A060775, A070824, A119313, A129308, A181063, A199970, A163870, A328448, A328449.
%K nonn,more
%O 0,2
%A _Gus Wiseman_, Oct 17 2019
%E a(12) from _Robert Israel_, Mar 31 2023
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