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URL: https://oeis.org/A286387

⇱ A286387 - OEIS

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A286387
a(n) = A002487(n^2).
3
0, 1, 1, 4, 1, 7, 4, 9, 1, 14, 7, 13, 4, 29, 9, 16, 1, 23, 14, 43, 7, 36, 13, 29, 4, 43, 29, 64, 9, 67, 16, 25, 1, 34, 23, 89, 14, 115, 43, 46, 7, 85, 36, 79, 13, 46, 29, 79, 4, 97, 43, 142, 29, 89, 64, 91, 9, 136, 67, 157, 16, 121, 25, 36, 1, 47, 34, 151, 23, 236, 89, 157, 14, 211, 115, 104, 43, 225, 46, 109, 7, 162, 85, 235, 36, 139, 79, 174, 13, 101, 46
OFFSET
0,4
COMMENTS
Conjecture: For all i >= 0, j >= 0: A103391(1+i) = A103391(1+j) => a(i) = a(j). This would be an implication of observation made at A286377, which has been checked up to n=2048. See also A286378.
FORMULA
a(n) = A002487(A000290(n)) = A002487(n^2).
PROG
(Scheme) (define (A286387 n) (A002487 (* n n)))
(Python)
from functools import reduce
def A286387(n): return sum(reduce(lambda x, y:(x[0], x[0]+x[1]) if int(y) else (x[0]+x[1], x[1]), bin(n**2)[-1:2:-1], (1, 0))) if n else 0 # Chai Wah Wu, May 18 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 09 2017
STATUS
approved