A340570 Averages k of twin prime pairs such that A075255(k) is also the average of a twin prime pair.

42, 72, 348, 1998, 4722, 9282, 28182, 34128, 34962, 46818, 46830, 57348, 59442, 71328, 79398, 81552, 97860, 113160, 115602, 117618, 138798, 151008, 157218, 158748, 179898, 183510, 184902, 185070, 234810, 244158, 245418, 284130, 316698, 328062, 335382, 337872, 343830, 351258, 357780, 425442

Offset

1,1

Comments

Terms k of A075255 such that A014574(k) is in A075255.

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Example

a(3) = 348 is a term because A014574(348) = 348-(2+2+3+29) = 312 and 348-1 = 347, 348+1 = 349, 312-1 = 311, and 312+1 = 313 are prime.

Maple

filter:= proc(n) local s, t;
  if not isprime(n-1) or not isprime(n+1) then return false fi;
  s:= add(t[1]*t[2], t= ifactors(n)[2]);
  isprime(n-s-1) and isprime(n-s+1)
end proc:
select(filter, [seq(i, i=6..10^6, 2)]);

Crossrefs

Cf. A014574, A075255.

Sequence in context: A340384 A330893 A305153 * A261621 A043689 A043573

Adjacent sequences: A340567 A340568 A340569 * A340571 A340572 A340573

Keyword

nonn

Author

J. M. Bergot and Robert Israel, Jan 11 2021

Status

approved