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A064440 A048138(n) is a prime and sets a new record for such primes. 1
6, 21, 31, 79, 121, 265, 271, 379, 541, 631 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

PROG

(PARI) f(n) = my(s=0); for(x=1, n^2, if(sigma(x)-x==n, s++)); s;

a=0; for(n=1, 10^5, x=f(n); if(isprime(x), b=x; if(b>a, a=b; print1(n, ", "))))

CROSSREFS

Sequence in context: A280296 A239920 A173622 * A106634 A261077 A063126

Adjacent sequences:  A064437 A064438 A064439 * A064441 A064442 A064443

KEYWORD

nonn,more

AUTHOR

Jason Earls (zevi_35711(AT)yahoo.com), Oct 01 2001

EXTENSIONS

Corrected and extended by Matthew Conroy, Oct 02 2001

STATUS

approved

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Last modified June 23 16:45 EDT 2017. Contains 288666 sequences.