A357143 a(n) is sum of the base-5 digits of n each raised to the number of digits of n in base 5.
1, 2, 3, 4, 1, 2, 5, 10, 17, 4, 5, 8, 13, 20, 9, 10, 13, 18, 25, 16, 17, 20, 25, 32, 1, 2, 9, 28, 65, 2, 3, 10, 29, 66, 9, 10, 17, 36, 73, 28, 29, 36, 55, 92, 65, 66, 73, 92, 129, 8, 9, 16, 35, 72, 9, 10, 17, 36, 73, 16, 17, 24, 43, 80, 35, 36, 43, 62, 99, 72, 73, 80, 99, 136, 27
Offset: 1
Examples
For n = 13_10 = 23_5 (2 digits in base 5): a(13) = 2^2 + 3^2 = 13. For n = 73_10 = 243_5 (3 digits in base 5): a(73) = 2^3 + 4^3 + 3^3 = 99.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
f:= proc(n) local L,d,i; L:= convert(n,base,5); d:= nops(L); add(L[i]^d,i=1..d) end proc: map(f,[$1..100]); # Robert Israel, Oct 26 2023
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Mathematica
a[n_] := Total[IntegerDigits[n, 5]^IntegerLength[n, 5]]; Array[a, 100] (* Amiram Eldar, Oct 30 2022 *)
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PARI
a(n) = my(d=digits(n, 5)); sum(k=1, #d, d[k]^#d); \\ Michel Marcus, Oct 29 2022
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Python
from sympy.ntheory.factor_ import digits def A357143(n): t = len(s:=digits(n,5)[1:]) return sum(d**t for d in s) # Chai Wah Wu, Oct 31 2022
Extensions
Corrected and extended by Michel Marcus, Oct 29 2022