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A037172
Numbers n such that sigma(n) - n = {number of primes <= n}.
2
1, 2, 9, 85, 2569, 2723, 2807, 174449, 1302379, 8513821, 10518107, 14348051, 70110091, 70111621, 70112369, 10910880311, 43908943297, 4224496855063
OFFSET
1,2
PROG
(PARI) isok(n) = (sigma(n)-n == primepi(n)) \\ Michel Marcus, Jul 14 2013
CROSSREFS
Sequence in context: A068595 A330475 A356615 * A106163 A368186 A359903
KEYWORD
nonn,more
EXTENSIONS
More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Apr 09 2002
a(16)-a(17) from Donovan Johnson, Sep 03 2008
a(18) from Giovanni Resta, Jul 05 2016
STATUS
approved