A152757 - OEIS

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A152757

Numbers k such that the deficiency of k plus the number of proper divisors of k is a prime number (see A152864).

2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 26, 27, 28, 29, 31, 34, 37, 38, 41, 43, 45, 46, 47, 49, 52, 53, 55, 57, 58, 59, 61, 62, 64, 67, 70, 71, 73, 74, 75, 76, 77, 79, 82, 83, 86, 88, 89, 91, 93, 94, 95, 97, 99, 101, 103, 104, 106, 107, 109, 110, 111

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

B. D. Swan, Table of n, a(n) for n = 1..50000

MAPLE

with(numtheory): a := proc (n) if isprime(2*n-sigma(n)+tau(n)-1) = true then n else end if end proc: seq(a(n), n = 1 .. 120); # Emeric Deutsch, Jan 08 2009

CROSSREFS

Cf. A000005, A000203, A033879, A032741, A152770, A152864.

Sequence in context: A236105 A292050 A048627 * A062462 A033948 A285514

Adjacent sequences: A152754 A152755 A152756 * A152758 A152759 A152760

KEYWORD

nonn

AUTHOR

Omar E. Pol, Dec 14 2008

EXTENSIONS

Extended by Emeric Deutsch, Jan 08 2009

Name edited by Jon E. Schoenfield, Jan 06 2019

STATUS

approved