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_Charles R Greathouse IV_, , <a href="/A136292/b136292.txt">Table of n, a(n) for n = 1..10000</a>
_Charles R Greathouse IV, _, <a href="/A136292/b136292.txt">Table of n, a(n) for n = 1..10000</a>
(PARI) v=[]; for(a=1, 50, for(b=1, a, for(c=1, b, for(d=1, c, for(e=1, d, if(ispseudoprime(t=a^a+b^b+c^c+d^d+e^e), v=concat(v, t))))))); v \\ _Charles R Greathouse IV, _, Feb 15 2011
_Jonathan Vos Post (jvospost3(AT)gmail.com), _, Apr 11 2008
proposed
approved
Charles R Greathouse IV, <a href="/A136292/b136292.txt">Table of n, a(n) for n = 1..10000</a>
a(5) = 37 = 1^1 + 1^1 + 2^2 + 2^2 + 3^3.
(PARI) v=[]; for(a=1, 50, for(b=1, a, for(c=1, b, for(d=1, c, for(e=1, d, if(ispseudoprime(t=a^a+b^b+c^c+d^d+e^e), v=concat(v, t))))))); v \\ Charles R Greathouse IV, Feb 15 2011
approved
proposed
Primes of the form a^a + b^b + c^c + d^d + e^e.
5, 11, 17, 31, 37, 43, 83, 89, 109, 263, 269, 521, 541, 547, 593, 773, 1051, 3181, 3187, 3413, 3691, 6763, 9377, 9403, 9887, 12527, 46663, 46993, 49787, 50549, 52937, 53189, 93851, 96697, 99563, 139999, 823547, 823553, 823573, 823651, 823831
1,1
a(1) = 5 = 1^1 + 1^1 + 1^1 + 1^1 + 1^1.
a(2) = 11 = 1^1 + 1^1 + 1^1 + 2^2 + 2^2.
a(3) = 17 = 1^1 + 2^2 + 2^2 + 2^2 + 2^2.
a(4) = 31 = 1^1 + 1^1 + 1^1 + 1^1 + 3^3.
a(5) = 37 = 1^1 + 1^1 + 2^2 + 2^2 + 3^3.
Select[Union[ Flatten[Table[ a^a + b^b + c^c + d^d + e^e, {a, 1, 20}, {b, 1, a}, {c, 1, b}, {d, 1, c}, {e, 1, d}]]], PrimeQ]
easy,nonn
Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 11 2008
approved