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A055813 Primes arising in A064205. 8
2, 5, 19, 263, 373, 1033, 65551, 123833, 283553, 292993, 2197633, 5778673, 12795193, 10500613, 19980283, 32213033, 36978853, 72494813, 140724953, 164119063, 183105509, 193710277, 320210941, 450065801, 268354393, 496922891, 506906473, 1333406021 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

a(3) = 19 since, for A064205(3) = 8, sigma(8)+tau(8) = 15+4 = 19, a prime number. - Michael De Vlieger, Dec 17 2016

MATHEMATICA

Select[Table[Total@ Map[DivisorSigma[#, n] &, {0, 1}], {n, 10^7}], PrimeQ] (* Michael De Vlieger, Dec 17 2016 *)

PROG

(PARI) lista(nn) = for (n=1, nn, if (isprime(p=sigma(n) + numdiv(n)), print1(p, ", "))); \\ Michel Marcus, Dec 18 2016

CROSSREFS

Sequence in context: A212269 A080280 A218386 * A119550 A119563 A270398

Adjacent sequences:  A055810 A055811 A055812 * A055814 A055815 A055816

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 22 2001

STATUS

approved

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Last modified April 4 05:34 EDT 2020. Contains 333212 sequences. (Running on oeis4.)