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A372290
Numbers that occur in the odd bisection of A371094.
7
21, 45, 69, 93, 117, 141, 165, 189, 213, 237, 261, 285, 309, 333, 341, 357, 381, 405, 429, 453, 477, 501, 525, 549, 573, 597, 621, 645, 669, 693, 717, 725, 741, 765, 789, 813, 837, 861, 885, 909, 933, 957, 981, 1005, 1029, 1053, 1077, 1101, 1109, 1125, 1149, 1173, 1197, 1221, 1245, 1269, 1293, 1317, 1341, 1365, 1389
OFFSET
1,1
COMMENTS
Numbers that occur in array A371100.
LINKS
EXAMPLE
21 is present because A371094(1) = A371094(3) = 21.
45 is present because A371094(7) = 45.
87381 is present because A371094(85) = A371094(213) = A371094(7281) = A371094(14563) = 87381.
PROG
(PARI)
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
isA372290(n) = if(!(n%2), 0, forstep(k=1, n, 2, if(A371094(k)==n, return(1))); (0));
(PARI)
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
A372290list(up_to_n) = { my(v=vector((1+up_to_n)/2), x, lista=List([])); forstep(k=1, up_to_n, 2, x=A371094(k); if(x <= up_to_n, v[(x+1)/2]++)); for(i=1, (1+up_to_n)/2, if(v[i]>0, listput(lista, i+i-1))); Vec(lista); };
CROSSREFS
Union of A372291 and A372292.
Cf. A102603 (subsequence), A371094, A371100.
Sequence in context: A317210 A099468 A063500 * A102603 A147222 A199767
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 26 2024
STATUS
approved