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A115801
Numbers k such that 9*k = A048720(25,k), where A048720 is carryless base-2 multiplication.
8
0, 15, 30, 31, 60, 62, 63, 120, 124, 126, 127, 240, 248, 252, 254, 255, 480, 496, 504, 508, 510, 511, 960, 992, 1008, 1016, 1020, 1022, 1023, 1920, 1984, 2016, 2032, 2040, 2044, 2046, 2047, 3840, 3855, 3968, 4032, 4064, 4080, 4088, 4092, 4094, 4095, 7680, 7695, 7710, 7711, 7936, 7951, 8064, 8128, 8160, 8176, 8184
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OFFSET
1,2
COMMENTS
If n is a term, then 2*n is also a term, and vice versa.
Conjecture: also k such that 15*k = A048720(19,k). This has been checked for all k in range 0 .. 2^25. - Antti Karttunen, Dec 21 2025
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
Index entries for sequences defined by congruent products between domains N and GF(2)[X]
Index entries for sequences related to binary expansion of n.
Index entries for sequences related to carryless arithmetic.
PROG
(PARI)
A048720(b, c) = fromdigits(Vec(Pol(binary(b))*Pol(binary(c)))%2, 2);
is_A115801(k) = (9*k == A048720(25, k)); \\ Antti Karttunen, Dec 21 2025
CROSSREFS
After the initial 0, row 9 of A115872, and by conjecture also the row 15.
Subsequence of A391744, and by conjecture also of A391850.
Cf. A115809 (conjectured to be a subsequence), A115811 (terms not present in A115809), A115802 (terms shown in binary).
Sequence in context: A095783 A348556 A067400 * A343343 A318992 A343337
Adjacent sequences: A115798 A115799 A115800 * A115802 A115803 A115804
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Feb 01 2006
EXTENSIONS
Offset corrected, more terms added and name edited by Antti Karttunen, Dec 21 2025
STATUS
approved

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Last modified May 21 17:47 EDT 2026. Contains 395800 sequences.
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