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A049653 a(n) = 2*n - prevprime(2*n). 15
1, 1, 1, 3, 1, 1, 3, 1, 1, 3, 1, 3, 5, 1, 1, 3, 5, 1, 3, 1, 1, 3, 1, 3, 5, 1, 3, 5, 1, 1, 3, 5, 1, 3, 1, 1, 3, 5, 1, 3, 1, 3, 5, 1, 3, 5, 7, 1, 3, 1, 1, 3, 1, 1, 3, 1, 3, 5, 7, 9, 11, 13, 1, 3, 1, 3, 5, 1, 1, 3, 5, 7, 9, 1, 1, 3, 5, 1, 3, 5, 1, 3, 1, 3, 5, 1, 3, 5, 1, 1, 3, 5, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 2..5000

FORMULA

a(n) = A049711(2*n). - R. J. Mathar, Oct 26 2015

MATHEMATICA

Table[2*n - NextPrime[2*n, -1], {n, 2, 50}] (* G. C. Greubel, Dec 05 2017 *)

PROG

(MAGMA) [2*n - NthPrime(#PrimesUpTo(2*n)): n in [2..50]]; // G. C. Greubel, Dec 05 2017

(PARI) for(n=2, 50, print1(2*n - precprime(2*n), ", ")) \\ G. C. Greubel, Dec 05 2017

CROSSREFS

Cf. A049613, A049711, A049716, A049847.

Sequence in context: A230405 A101685 A238737 * A281680 A060266 A073310

Adjacent sequences:  A049650 A049651 A049652 * A049654 A049655 A049656

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 15 18:10 EST 2018. Contains 317240 sequences. (Running on oeis4.)