OFFSET
0,2
EXAMPLE
The sequence of terms > 1 together with their nontrivial divisors begins:
2: {}
6: {2,3}
12: {2,3,4,6}
60: {2,3,4,5,6,10,12,15,20,30}
420: {2,3,4,5,6,7,10,12,14,15,20,21,28,30,35,42,60,70,84,105,140,210}
504: {2,3,4,6,7,8,9,12,14,18,21,24,28,36,42,56,63,72,84,126,168,252}
MATHEMATICA
dav=Table[Switch[n, 1, 1, _, Max@@Length/@Split[DeleteCases[Divisors[n], 1|n], #2==#1+1&]], {n, 1000}];
Table[Position[dav, i][[1, 1]], {i, Union[dav]}]//Sort
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Oct 17 2019
EXTENSIONS
a(12) from Robert Israel, Mar 31 2023
STATUS
approved