A185353 a(n) = (1^1 + 2^2 . . . + n^n) mod 10.

1, 5, 2, 8, 3, 9, 2, 8, 7, 7, 8, 4, 7, 3, 8, 4, 1, 5, 4, 4, 5, 9, 6, 2, 7, 3, 6, 2, 1, 1, 2, 8, 1, 7, 2, 8, 5, 9, 8, 8, 9, 3, 0, 6, 1, 7, 0, 6, 5, 5, 6, 2, 5, 1, 6, 2, 9, 3, 2, 2, 3, 7, 4, 0, 5, 1, 4, 0, 9, 9, 0, 6, 9, 5, 0, 6, 3, 7, 6, 6, 7, 1, 8, 4, 9, 5, 8, 4, 3, 3, 4, 0, 3, 9, 4, 0, 7, 1, 0, 0

Offset

1,2

Comments

The last digit of 1^1 + 2^2 +...+ n^n, which has period 100.

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Mathematica

Mod[Accumulate[Table[n^n, {n, 200}]], 10] (* T. D. Noe, Jan 27 2012 *)

Prog

(PARI) a(n) = sum(k=1, n, k^k) % 10; \\ Michel Marcus, Jun 28 2017
(Python)
from itertools import accumulate, count, islice
def A185353_gen(): # generator of terms
    yield from accumulate((pow(k, k, 10) for k in count(1)), func=lambda x, y:(x+y)%10)
A185353_list = list(islice(A185353_gen(), 40)) # Chai Wah Wu, Jun 17 2022

Crossrefs

Cf. A000312 (n^n), A001923 (1^1 + 2^2 +...+ n^n).

Sequence in context: A155975 A152956 A099873 * A345712 A355972 A168202

Adjacent sequences: A185350 A185351 A185352 * A185354 A185355 A185356

Keyword

nonn

Author

Muhammed Hedayet, Jan 26 2012

Extensions

Extended by T. D. Noe, Jan 27 2012

Status

approved