A138866 Concatenation of first 3 digits and last 3 digits of n-th Mersenne prime A000668(n).

33, 77, 3131, 127127, 819191, 131071, 524287, 214647, 230951, 618111, 162127, 170727, 686151, 531127, 104087, 147007, 446351, 259071, 190991, 285607, 478111, 346551, 281191, 431471, 448751, 402511, 854671, 536207, 521007, 512311, 746447, 174887, 129591, 412527, 814711, 623151, 127271, 437791, 924071, 125047, 299407, 122247, 315871, 124871, 202927, 169751, 316511

Offset

1,1

Links

Table of n, a(n) for n=1..47.

L. C. Noll, Mersenne Prime Digits and Names.

Mathematica

Join[{33, 77, 3131}, FromDigits[Flatten[Join[{Take[IntegerDigits[#], 3], Take[ IntegerDigits[ #], -3]}]]]&/@ (2^MersennePrimeExponent[Range[4, 40]]-1)] (* Harvey P. Dale, Dec 30 2023 *)

Crossrefs

Cf. A000668, A080173, A104511, A138816, A138817, A138840, A138841.

Sequence in context: A378481 A211837 A138863 * A001987 A094846 A044171

Adjacent sequences: A138863 A138864 A138865 * A138867 A138868 A138869

Keyword

base,nonn

Author

Omar E. Pol, Apr 02 2008

Extensions

More terms from Harvey P. Dale, Dec 30 2023

Status

approved