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A073718 Powers of 2 with composite exponents. 2
16, 64, 256, 512, 1024, 4096, 16384, 32768, 65536, 262144, 1048576, 2097152, 4194304, 16777216, 33554432, 67108864, 134217728, 268435456, 1073741824, 4294967296, 8589934592, 17179869184, 34359738368, 68719476736 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..24.

Index to divisibility sequences

FORMULA

a(n) = 2^A002808(n) = A000079(A002808(n)).

Sum_{n>=1} 1/a(n) = A275306. - Amiram Eldar, Aug 11 2020

MATHEMATICA

Table[2^FixedPoint[n+PrimePi[ # ]+1&, n], {n, 1, 30}]

PROG

(PARI) for(n=4, 100, if(!isprime(n), print1(2^n", "))) \\ Charles R Greathouse IV, Apr 09 2012

CROSSREFS

Cf. A000079, A002808, A275306.

Sequence in context: A212512 A317235 A255661 * A230970 A061449 A168091

Adjacent sequences:  A073715 A073716 A073717 * A073719 A073720 A073721

KEYWORD

easy,nonn

AUTHOR

Labos Elemer, Aug 05 2002

STATUS

approved

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Last modified September 26 20:34 EDT 2021. Contains 347672 sequences. (Running on oeis4.)