login
A372282
Array read by upward antidiagonals: A(n, k) = A371094(A(n-1, k)) for n > 1, k >= 1; A(1, k) = 2*k-1.
18
1, 21, 3, 5461, 21, 5, 357913941, 5461, 341, 7, 1537228672809129301, 357913941, 1398101, 45, 9, 28356863910078205288614550619314017621, 1537228672809129301, 23456248059221, 1109, 117, 11, 9649340769776349618630915417390658987772498722136713669954798667326094136661, 28356863910078205288614550619314017621, 6602346876188694799461995861, 873813, 11605, 69, 13
OFFSET
1,2
EXAMPLE
Array begins:
n\k| 1 2 3 4 5 6 7 8 9 10
---+----------------------------------------------------------------------
1 | 1, 3, 5, 7, 9, 11, 13, 15, 17, 19,
2 | 21, 21, 341, 45, 117, 69, 341, 93, 213, 117,
3 | 5461, 5461, 1398101, 1109, 11605, 3413, 1398101, 2261, 87381, 11605,
PROG
(PARI)
up_to = 28;
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
A372282sq(n, k) = if(1==n, 2*k-1, A371094(A372282sq(n-1, k)));
A372282list(up_to) = { my(v = vector(up_to), i=0); for(a=1, oo, for(col=1, a, i++; if(i > up_to, return(v)); v[i] = A372282sq((a-(col-1)), col))); (v); };
v372282 = A372282list(up_to);
A372282(n) = v372282[n];
CROSSREFS
Cf. A005408 (row 1), A372351 (row 2, bisection of A371094), A372444 (column 14).
Arrays derived from this one:
A372285 the number of terms of A086893 in the interval [A(n, k), A(1+n, k)],
A372287 the column index of A(n, k) in array A257852,
A372288 the sum of digits of A(n, k) in "Jacobsthal greedy base",
A372353 differences between A(n,k) and the largest term of A086893 <= A(n,k),
A372354 floor(log_2(.)) of terms, A372356 (and their columnwise first differences),
A372359 terms xored with binary words of the same length, either of the form 10101...0101 or 110101...0101, depending on whether the binary length is odd or even.
Cf. also arrays A371096, A371102 that give subsets of columns of this array, and array A371100 that gives the terms of the row 2 in different order.
Sequence in context: A077690 A018855 A349873 * A263277 A040428 A040429
KEYWORD
nonn,tabl,easy
AUTHOR
Antti Karttunen, Apr 28 2024
STATUS
approved