OFFSET
0,2
LINKS
Giovanni Resta, Table of n, a(n) for n = 0..54
EXAMPLE
The sequence of terms together with their non-singleton runs of divisors begins:
1: {}
2: {{1,2}}
20: {{1,2},{4,5}}
90: {{1,2,3},{5,6},{9,10}}
630: {{1,2,3},{5,6,7},{9,10},{14,15}}
MATHEMATICA
dv=Table[Length[DeleteCases[Length/@Split[Divisors[n], #2==#1+1&], 1]], {n, 1000}];
Table[Position[dv, i][[1, 1]], {i, Union[dv]}]
CROSSREFS
Equal {1} followed by the positions of first appearances in A328511 (times 2).
The longest run of divisors of n has length A055874.
Numbers whose divisors have no non-singleton runs are A005408.
The number of successive pairs of divisors of n is A129308(n).
The number of singleton runs of divisors is A132881.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 18 2019
EXTENSIONS
Offset changed to 0 and a(10)-a(30) added by Giovanni Resta, Oct 25 2019
STATUS
approved