A046853 Denominator of sum of reciprocals of first n palindromic primes.

2, 6, 30, 210, 2310, 233310, 30563610, 4615105110, 835334024910, 159548798757810, 49938774011194530, 17628387225951669090, 6575388435279972570570, 2518373770712229494528310

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Example

1/2 + 1/3 + 1/5 + 1/7 + 1/11 + 1/101 + ... gives 1/2, 5/6, 31/30, 247/210, ...

Mathematica

palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]; Denominator[Accumulate[1/#&/@Select[Prime[Range[100]], palQ]] (* Vincenzo Librandi, Dec 30 2011 *)
Accumulate[1/Select[Prime[Range[100]], PalindromeQ]]//Denominator (* Harvey P. Dale, Jul 24 2021 *)

Crossrefs

Cf. A046852, A002385.

Sequence in context: A088257 A058694 A336672 * A136351 A071290 A185693

Adjacent sequences: A046850 A046851 A046852 * A046854 A046855 A046856

Keyword

nonn,base,easy

Author

G. L. Honaker, Jr.

Extensions

More terms from Erich Friedman, Jun 03 2001

Status

approved