A101754 Numbers n such that the sum of the first n decimal places of Catalan's constant is prime.

9, 11, 14, 22, 23, 25, 31, 32, 39, 45, 46, 55, 56, 57, 63, 64, 68, 73, 78, 81, 84, 90, 94, 112, 115, 117, 162, 163, 169, 172, 179, 184, 200, 208, 212, 221, 227, 233, 240, 253, 270, 272, 283, 290, 303, 327, 329, 339, 345, 347, 348, 365, 378, 381, 396, 398, 409

Offset

1,1

Links

Table of n, a(n) for n=1..57.

Example

The sums of the first n decimal places of Catalan's constant are listed in A099616: 9, 10, 15, 24, 30, 35, 40, 49, 53, 54, 61, ... Of these, the first one that is prime is 53 which is the 9th term. The first term in our sequence is therefore 9. The partial sum 61 is also prime and this appears in the 11th place, so the second term of our sequence is 11.

Mathematica

Flatten[Position[Accumulate[RealDigits[N[Catalan, 500]][[1]]], _?PrimeQ]] (* Harvey P. Dale, May 10 2011 *)

Crossrefs

Cf. A099616.

Sequence in context: A307188 A212816 A183980 * A348614 A113339 A270190

Adjacent sequences: A101751 A101752 A101753 * A101755 A101756 A101757

Keyword

nonn,base

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Dec 15 2004

Status

approved