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 A276455 Primes of the form Sum_{k=1..n} k^(k-1). 0
 3, 701, 45269999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Searched up to n = 5000. a(4) has 38019 digits (1973212031 ... 7493445627) and corresponds to n=9553. - Robert Price, Sep 23 2016; [number of digits in a(4) corrected by Jon E. Schoenfield, Nov 06 2016] No other primes corresponding to n < 80000. - Robert Price, Mar 17 2017 LINKS Sebastiao Antonio da Silva, Prime Curios: 9^8 + 8^7 + 7^6 + 6^5 + 5^4 + 4^3 + 3^2 + 2^1 + 1^0 is prime EXAMPLE 3 is in the sequence because 3 is prime and 3 = 2^1 + 1^0. 701 is in the sequence because 701 is prime and 701 = 5^4 + 4^3 + 3^2 + 2^1 + 1^0. 45269999 is in the sequence because 45269999 is prime and 45269999 = 9^8 + 8^7 + 7^6 + 6^5 + 5^4 + 4^3 + 3^2 + 2^1 + 1^0. MATHEMATICA Select[Accumulate[Table[n^(n-1), {n, 100}]], PrimeQ] (* Harvey P. Dale, Apr 13 2020 *) PROG (Sage) sum = 0 seq = [] max_n = 2500 for n in range(1, max_n+1):     sum += n^(n-1)     if is_prime(sum):         seq.append(n) print(seq) CROSSREFS Primes in A060946. Sequence in context: A266639 A203496 A308323 * A231604 A306961 A059120 Adjacent sequences:  A276452 A276453 A276454 * A276456 A276457 A276458 KEYWORD nonn,bref AUTHOR Robert C. Lyons, Sep 06 2016 STATUS approved

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Last modified May 15 12:37 EDT 2021. Contains 343920 sequences. (Running on oeis4.)