A133026 Concatenation of next n Fermat numbers A000215.

3, 517, 257655374294967297

Offset: 1

Author

Omar E. Pol, Nov 09 2007

Keywords

• base
• easy
• nonn

Comments

a(4) has 292 digits and is too large to include.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..4

Crossrefs

Cf. A000215, A053067, A133013.

Programs

Mathematica

a[n_] := FromDigits[Flatten[IntegerDigits[Table[2^(2^(k - 1)) + 1, {k, n*(n - 1)/2 + 1, n*(n + 1)/2}]]]]; Array[a, 3] (* Amiram Eldar, Jul 09 2025 *)