A046431 Sum of digits of a(n) raised to its digits powers is prime.

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

Marius A. Burtea, Table of n, a(n) for n = 0..5000

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

Cf. A046432-A046441.

Sequence in context: A110186 A098945 A323190 * A108697 A109279 A258744

Adjacent sequences: A046428 A046429 A046430 * A046432 A046433 A046434

Keyword

nonn,base

Author

Patrick De Geest, Jul 15 1998

Status

approved