A135620 a(n) = 2^(prime(n) - 2).

1, 2, 8, 32, 512, 2048, 32768, 131072, 2097152, 134217728, 536870912, 34359738368, 549755813888, 2199023255552, 35184372088832, 2251799813685248, 144115188075855872, 576460752303423488, 36893488147419103232, 590295810358705651712, 2361183241434822606848, 151115727451828646838272

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..465

Formula

a(n) = 2^(A000040(n)-2) = 2^(A040976(n)) = 2^A000040(n)/4 = A061286(n)/2.

Mathematica

Table[2^(Prime[n] - 2), {n, 1, 25}] (* G. C. Greubel, Oct 23 2016 *)

Prog

(Magma) [2^(NthPrime(n)-2): n in [1..25]]; // Vincenzo Librandi, Oct 23 2016
(PARI) a(n) = 2^(prime(n)-2); \\ Michel Marcus, Oct 23 2016

Crossrefs

Cf. A000040, A040976, A061286.

Partial differences of A135482.

Sequence in context: A063505 A085466 A084039 * A134708 A294530 A037513

Adjacent sequences: A135617 A135618 A135619 * A135621 A135622 A135623

Keyword

easy,nonn

Author

Omar E. Pol, Mar 01 2008

Status

approved