1,1

a(n) = Min{p; A001221[p+2]=n}

For n = 1,...,7 the factors of 2+a(n) are as follows: 2.2, 3.5, 3.5.7, 3.5.7.11, 3.5.7.11.13, 3.5.7.11.13.17, 3.5.7.11.13.17.19; i.e. a[n] = A002110(n+1)/2 which is prime for n = 2,..,7.

Cf. A001221, A002110, A067023, A053705.

Adjacent sequences: A067021 A067022 A067023 this_sequence A067025 A067026 A067027

Sequence in context: A113598 A125589 A007809 this_sequence A103513 A083062 A127746

nonn

Labos E. (labos(AT)ana.sote.hu), Dec 29 2001