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1, 31, 179, 585, 1463, 3065, 5729, 9797, 15737, 24087, 35315, 50073, 69025, 92871, 122475, 158681, 202529, 254597, 315957, 387977, 471589, 568227, 678971, 805241, 948515, 1109675, 1290839, 1493127, 1717571, 1966997, 2242925, 2547277, 2881033, 3246087, 3645459
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (2*n+1)^2 + Sum_{i=2..2n+1} (2*n+2-i)*(4*n+4-i)*phi(i). - Chai Wah Wu, Aug 17 2021
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PROG
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(Python)
from sympy import totient
def A331759(n): return (2*n+1)**2 + sum(totient(i)*(2*n+2-i)*(4*n+4-i) for i in range(2, 2*n+2)) # Chai Wah Wu, Aug 17 2021
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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