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A013606 a(n) = 4^n - prevprime(4^n). 2
1, 3, 3, 5, 3, 3, 3, 15, 5, 3, 3, 3, 5, 57, 35, 5, 41, 5, 45, 87, 11, 17, 21, 59, 27, 47, 33, 5, 27, 93, 57, 59, 5, 23, 35, 93, 35, 15, 11, 65, 57, 35, 35, 299, 33, 83, 3, 17, 51, 15, 33, 17, 117, 59, 21, 75, 11, 3, 5, 119, 3, 59, 137, 159, 5, 347, 45, 113, 105, 27, 111 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Daniel Starodubtsev, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A000302(n) - A104089(n). - Michel Marcus, Sep 01 2019

MAPLE

seq(4^i-prevprime(4^i), i=1..100);

MATHEMATICA

#-NextPrime[#, -1]&/@(4^Range[80]) (* Harvey P. Dale, Dec 13 2016 *)

PROG

(PARI) a(n) = 4^n - precprime(4^n); \\ Michel Marcus, Sep 01 2019

CROSSREFS

Cf. A000302, A104089.

Sequence in context: A333596 A066670 A282270 * A206550 A284723 A190911

Adjacent sequences: A013603 A013604 A013605 * A013607 A013608 A013609

KEYWORD

nonn

AUTHOR

James Kilfiger (mapdn(AT)csv.warwick.ac.uk)

STATUS

approved

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Last modified December 9 23:05 EST 2022. Contains 358710 sequences. (Running on oeis4.)