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.

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

Links

Table of n, a(n) for n=1..28.

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:

A372283,

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

Adjacent sequences: A372279 A372280 A372281 * A372283 A372284 A372285

Keyword

nonn,tabl,easy

Author

Antti Karttunen, Apr 28 2024

Status

approved