login
A372557
Numbers k such that the least number of Jacobsthal numbers that add up to k, A372555(k), is less than the number needed with the greedy algorithm, A265745(k).
4
63, 84, 148, 169, 191, 212, 234, 255, 276, 297, 319, 340, 404, 425, 489, 510, 532, 553, 575, 596, 617, 638, 660, 681, 703, 724, 746, 767, 788, 809, 831, 852, 874, 895, 917, 937, 938, 959, 980, 1002, 1022, 1023, 1044, 1065, 1087, 1108, 1129, 1150, 1172, 1193, 1215, 1236, 1258, 1278, 1279, 1300, 1321, 1343, 1363, 1364, 1428
OFFSET
1,1
LINKS
EXAMPLE
63 = 21+21+21 has A372555(63)=3 for its optimal, non-greedy solution, and A265745(63) = 5 for its greedy solution 63 = 43+11+5+3+1, therefore 63 is included in this sequence. (From Yuriko Suwa's Jul 11 2021 comment in A265745.)
84 = 21+21+21+21 has A372555(84)=4 for its optimal, non-greedy solution, and A265745(84) = 6 for its greedy solution 84 = 43+21+11+5+3+1, therefore 84 is included in this sequence.
169 = 85+21+21+21+21 has A372555(169)=5 for its optimal, non-greedy solution, and A265745(169) = 7 for its greedy solution 169 = 85+43+21+11+5+3+1, therefore 169 is included in this sequence.
PROG
(PARI)
;; For A372555, use the program given under that entry.
A130249(n) = (#binary(3*n+1)-1);
A001045(n) = (2^n - (-1)^n) / 3;
A265745(n) = { my(s=0); while(n, s++; n -= A001045(A130249(n))); (s); };
isA372557(k) = (A372555(k)<A265745(k));
CROSSREFS
Cf. A372558 (subsequence).
Sequence in context: A046049 A240528 A320066 * A372558 A125112 A043186
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 07 2024
STATUS
approved