A075781 Primes of the form perfect_power(n)+n.
2, 11, 13, 31, 59, 113, 313, 349, 659, 821, 1493, 1571, 1733, 3209, 3323, 5569, 7331, 7853, 10531, 13367, 17321, 21493, 21787, 25793, 30137, 31541, 36709, 39043, 39439, 44771, 46049, 49991, 55147, 55501, 56923, 57881, 58363, 59333, 65323
Offset: 1
Keywords
Examples
11 is OK: 11 = perfect_power(3) + 3 = 8 + 3, perfect_power(n) is n-th perfect power: A001597(n). 31 is OK: 31 = perfect_power(6) + 6 = 25 + 6; 59 is OK: 59 = perfect_power(10) + 10 = 49 + 10.
Crossrefs
Cf. A001597.
Programs
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PARI
lista(nn) = {vec = vector(nn, i, i); pp = select(i->((ispower(i) || (i==1))), vec); for (i = 1, #pp, if (isprime(pp[i]+i), print1(pp[i]+i, ", ")););} \\ Michel Marcus, Oct 03 2013