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A345005 Odd numbers whose arithmetic derivative (A003415) is equal to Dedekind psi (A001615) applied to the same number. 5
81, 3375, 15625, 231525, 713097, 1058841, 1500625, 4348377, 5764801, 16891497, 163555875, 209548647, 239010993, 239160735, 254205875, 267651475, 405189675, 451699875, 958403475, 1050284375, 1213014231, 1501534375, 1695809375, 1809323971, 1942143291 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Conjectured to be also the odd numbers k for which A344998(k) = A344999(k).
LINKS
PROG
(PARI)
A001615(n) = if(1==n, n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
isA345005(n) = ((n%2)&&(A003415(n)==A001615(n)));
CROSSREFS
Odd terms in A301939, but see also A345003.
Sequence in context: A254415 A017744 A232945 * A223477 A237842 A223501
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Jun 05 2021
STATUS
approved

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Last modified April 22 12:13 EDT 2024. Contains 371900 sequences. (Running on oeis4.)