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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 (list; graph; refs; listen; history; text; internal format)
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
Sequence in context: A110186 A098945 A323190 * A108697 A109279 A258744
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jul 15 1998
STATUS
approved

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Last modified March 1 15:29 EST 2024. Contains 370440 sequences. (Running on oeis4.)