OFFSET
0,1
COMMENTS
Indices of the first occurrence of value 2*n in A368945.
SRS(a(n)) has an even number of parts.
The maximum possible central 0 width extent in SRS(n) for odd numbers n is 2*n - (n+1) - 2 = n - 3. This is achieved only by odd prime numbers which form a subsequence.
Conjecture: a(n) != -1 for all n >= 0.
FORMULA
EXAMPLE
a(2) = 7 since prime 7 is the smallest number whose central extent of width 0 equals 4.
a(3) = 22 since 22 is the smallest number whose central extent of width 0 equals 6.
MATHEMATICA
(* Function extent0[ ] is defined in A368945 *)
smallest[n_] := NestWhile[#+1&, n, extent0[#]!=n&]/; EvenQ[n]
a370204[n_] := Map[smallest[2#]&, Range[0, n]]
a370204[65]
CROSSREFS
KEYWORD
nonn
AUTHOR
Hartmut F. W. Hoft, Feb 11 2024
STATUS
approved