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A125236 Numbers n for which the absolute value of the abundance of n^2 is a prime number. 3
3, 5, 6, 7, 9, 10, 11, 14, 15, 17, 18, 22, 24, 26, 28, 29, 30, 31, 33, 34, 35, 44, 47, 50, 56, 58, 61, 65, 66, 67, 68, 69, 71, 72, 74, 75, 80, 85, 91, 94, 96, 97, 100, 101, 102, 104, 116, 118, 120, 121, 124, 125, 127, 131, 134, 136, 139, 144, 148, 149, 152, 164, 166, 170 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..64.

EXAMPLE

n=5: n^2=25, sigma[25]=25+5+1=31, 2*25=50, abundance=-19.

PROG

(PARI) for(n=1, 170, if(isprime(abs(sigma(n^2)-2*n^2)), print1(n, ", "))) - Klaus Brockhaus, Nov 25 2006

CROSSREFS

Cf. A088005.

Sequence in context: A186145 A047984 A288513 * A137624 A238246 A099467

Adjacent sequences:  A125233 A125234 A125235 * A125237 A125238 A125239

KEYWORD

nonn

AUTHOR

Jason G. Wurtzel, Nov 25 2006

EXTENSIONS

More terms from Klaus Brockhaus, Nov 25 2006

STATUS

approved

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Last modified September 24 22:27 EDT 2018. Contains 315360 sequences. (Running on oeis4.)