login
A327862
Numbers whose arithmetic derivative is of the form 4k+2, cf. A003415.
19
9, 21, 25, 33, 49, 57, 65, 69, 77, 85, 93, 121, 129, 133, 135, 141, 145, 161, 169, 177, 185, 201, 205, 209, 213, 217, 221, 237, 249, 253, 265, 289, 301, 305, 309, 315, 321, 329, 341, 351, 361, 365, 375, 377, 381, 393, 413, 417, 437, 445, 453, 459, 469, 473, 481, 485, 489, 493, 495, 497, 501, 505, 517, 529, 533, 537
OFFSET
1,1
COMMENTS
All terms are odd because the terms A068719 are either multiples of 4 or odd numbers.
Odd numbers k for which A064989(k) is one of the terms of A358762. - Antti Karttunen, Nov 30 2022
The second arithmetic derivative (A068346) of these numbers is odd. See A235991. - Antti Karttunen, Feb 06 2024
LINKS
PROG
(PARI)
A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
isA327862(n) = (2==(A003415(n)%4));
k=1; n=0; while(k<105, if(isA327862(n), print1(n, ", "); k++); n++);
CROSSREFS
Setwise difference A235992 \ A327864.
Setwise difference A046337 \ A360110.
Union of A369661 (k' has an even number of prime factors) and A369662 (k' has an odd number of prime factors).
Subsequences: A001248 (from its second term onward), A108181, A327978, A366890 (when sorted into ascending order), A368696, A368697.
Cf. A003415, A064989, A068346, A068719, A327863, A327865, A353495 (characteristic function).
Sequence in context: A188159 A272600 A359161 * A108181 A368696 A369661
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 30 2019
STATUS
approved