A270311 Indices of primes ending with the same decimal digit as the previous or next prime.

34, 35, 42, 43, 53, 54, 61, 62, 68, 69, 80, 81, 82, 83, 101, 102, 106, 107, 115, 116, 125, 126, 127, 128, 138, 139, 141, 142, 145, 146, 154, 155, 157, 158, 172, 173, 175, 176, 177, 178, 191, 192, 193, 194, 204, 205, 222, 223, 233, 234, 258, 259, 260, 266, 267, 269, 270, 279, 280, 289, 290, 306, 307

Offset

1,1

Links

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

Mathematica

Select[Range@ 307, Function[k, Or[k == Mod[NextPrime@ Prime@ #, 10], k == Mod[NextPrime[Prime@ #, -1], 10]]]@ Mod[Prime@ #, 10] &] (* Michael De Vlieger, Mar 15 2016 *)
PrimePi/@Select[Partition[Prime[Range[350]], 3, 1], Mod[#[[2]], 10]==Mod[#[[1]], 10]||Mod[#[[2]], 10]==Mod[#[[3]], 10]&][[;; , 2]] (* Harvey P. Dale, Mar 07 2024 *)

Crossrefs

Cf. A270310.

Sequence in context: A271984 A254756 A203462 * A257315 A045561 A294282

Adjacent sequences: A270308 A270309 A270310 * A270312 A270313 A270314

Keyword

nonn,base

Author

Francois Alcover, Mar 15 2016

Extensions

More terms from Michael De Vlieger, Mar 15 2016

Status

approved