A144550 Largest non-twin prime < n-th and (n+1)-th twin primes.

2, 23, 37, 53, 67, 97, 131, 173, 223, 233, 263, 277, 307, 337, 409, 457, 509, 563, 593, 613, 631, 653, 797, 853, 877, 1013, 1039, 1087, 1129, 1223, 1259, 1283, 1297, 1307, 1423, 1447, 1471, 1601, 1613, 1663, 1693, 1709, 1783, 1867, 1913, 1993, 2017, 2069

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

{A007510(k): nextprime(A007510(k)) in A077800}. - R. J. Mathar, May 01 2010

Maple

isA077800 := proc(n) isprime(n) and ( isprime(n+2) or isprime(n-2)) ; end proc:
isA007510 := proc(n) isprime(n) and not isA077800(n) ; end proc:
isA144550 := proc(n) isA007510(n) and isA077800( nextprime(n)) ; end proc:
for n from 2 to 2500 do if isA144550(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, May 01 2010

Mathematica

Module[{nn=400, tps}, tps=Union[Flatten[Select[Partition[Prime[Range[nn]], 2, 1], #[[2]]-#[[1]] == 2&]]]; Complement[NextPrime[#, -1]&/@tps, tps]] (* Harvey P. Dale, Jun 23 2022 *)

Crossrefs

Cf. A077800, A088175.

Sequence in context: A061448 A007510 A117242 * A106736 A045392 A107374

Adjacent sequences: A144547 A144548 A144549 * A144551 A144552 A144553

Keyword

nonn

Author

Juri-Stepan Gerasimov, Dec 31 2008

Extensions

Corrected (1993 inserted) by R. J. Mathar, May 01 2010

Status

approved