A358030 Decimal expansion of the constant Sum_{j>=0} j!!/prime(j)#, where prime(j)# indicates the j-th primorial number and j!! is the double factorial of j.

1, 9, 7, 9, 7, 7, 0, 6, 3, 3, 0, 6, 8, 0, 2, 8, 6, 8, 1, 9, 7, 0, 0, 0, 6, 0, 7, 5, 4, 1, 5, 6, 5, 4, 5, 0, 0, 6, 9, 3, 1, 1, 9, 3, 1, 7, 9, 8, 3, 8, 7, 9, 5, 6, 2, 4, 2, 0, 6, 4, 0, 0, 3, 4, 6, 5, 4, 7, 6, 1, 5, 6, 3, 1, 4, 5, 1, 2, 5, 0, 1, 0, 2, 0, 2, 2, 6

Offset

1,2

Links

Table of n, a(n) for n=1..87.

Formula

Equals Sum_{j>=0} A006882(j)/A002110(j).

Example

1.979770633068...

Mathematica

primorial[n_?Positive] := Product[Prime[i], {i, 1, n}];
RealDigits[1 + Sum[i!!/primorial[i], {i, 1, 500}], 10, 107][[1]]

Crossrefs

Cf. A002110, A006882, A357969.

Sequence in context: A243263 A244691 A121911 * A010547 A011405 A268228

Adjacent sequences: A358027 A358028 A358029 * A358031 A358032 A358033

Keyword

cons,easy,nonn

Author

Marco Ripà, Nov 12 2022

Status

approved