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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 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.)