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A046431
Sum of digits of a(n) raised to its digits powers is prime.
11
10, 11, 12, 14, 20, 21, 23, 27, 32, 34, 40, 41, 43, 47, 72, 74, 100, 101, 103, 110, 111, 113, 130, 131, 157, 175, 236, 263, 289, 298, 300, 301, 310, 311, 326, 348, 355, 362, 384, 438, 445, 454, 458, 483, 485, 507, 517, 535, 544, 548, 553, 570, 571, 584, 623
OFFSET
0,1
COMMENTS
If p is prime, then R_p (see A002275) is a term, so the sequence is infinite. - Marius A. Burtea, Sep 18 2019
LINKS
EXAMPLE
10 is a term: 10 -> 1^1 + 0^0 = 2 (prime).
289 is a term: 289 -> 2^2 + 8^8 + 9^9 = 404197709 (prime).
MAPLE
q:= n-> (l-> isprime(add(i^i, i=l)))(convert(n, base, 10)):
select(q, [$0..1000])[]; # Alois P. Heinz, Sep 18 2019
MATHEMATICA
sopQ[n_] := PrimeQ[Total[#^# & /@ (IntegerDigits[n] /. {0 -> 1})]]; Select[Range[625], sopQ[#] &] (* Jayanta Basu, Jun 25 2013 *)
PROG
(Magma) [k:k in [1..650]| IsPrime( &+[a[s]^(a[s]): s in [1..# a]]) where a is Intseq(k) ]; // Marius A. Burtea, Sep 18 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jul 15 1998
STATUS
approved