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A369664
Numbers k of the form 4m+1, whose arithmetic derivative k' is of the form 4u+2, and k' has an odd number of prime factors.
4
65, 77, 141, 161, 185, 201, 209, 221, 301, 305, 321, 341, 365, 377, 381, 413, 437, 453, 481, 485, 497, 501, 537, 545, 589, 649, 681, 689, 717, 721, 729, 737, 745, 749, 785, 789, 849, 893, 901, 905, 917, 921, 989, 1037, 1073, 1081, 1101, 1121, 1133, 1141, 1157, 1165, 1169, 1189, 1205, 1253, 1261, 1293, 1313, 1317
OFFSET
1,1
LINKS
PROG
(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
isA369664(n) = if(1!=(n%4), 0, my(d=A003415(n)); (2==(d%4) && (bigomega(d)%2)));
CROSSREFS
Intersection of A016813 and A369662.
Subsequence of A369666.
Sequence in context: A113688 A364028 A369662 * A214484 A159758 A056693
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 06 2024
STATUS
approved