A372560 Array read by upward antidiagonals: A(n, k) = A371094(A(n-1, k)) for n > 1, k >= 1; A(1, k) = A372443(k-1).

27, 165, 41, 8021, 501, 31, 12408149, 48469, 189, 47, 19607957362005, 299193685, 4565, 285, 71, 32439509492992549521282389, 7552911875069269, 1758549, 6869, 429, 107, 58947232705679751034215288252890081792789279233365, 3195535888075328282939605996885, 173230347605, 2643285, 10325, 645, 161

Offset

1,1

Links

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

Example

Array begins:
n\k|        1          2        3        4        5         6           7
---+-----------------------------------------------------------------------
1  |       27,        41,      31,      47,      71,      107,        161,
2  |      165,       501,     189,     285,     429,      645,       1941,
3  |     8021,     48469,    4565,    6869,   10325,    31061,     374101,
4  | 12408149, 299193685, 1758549, 2643285, 7951701, 95769941, 9216283989,

Prog

(PARI)
up_to = 28;
A000265(n) = (n>>valuation(n, 2));
A372443(n) = { my(x=27); while(n, x=A000265(3*x+1); n--); (x); };
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
A372560sq(n, k) = if(1==n, A372443(k-1), A371094(A372560sq(n-1, k)));
A372560list(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] = A372560sq((a-(col-1)), col))); (v); };
v372560 = A372560list(up_to);
A372560(n) = v372560[n];

Crossrefs

Cf. A371094, A372282, A372443 (the top row), A372444 (the leftmost column), A372561.

Sequence in context: A224001 A042418 A042420 * A213285 A372444 A174617

Adjacent sequences: A372557 A372558 A372559 * A372561 A372562 A372563

Keyword

nonn,tabl

Author

Antti Karttunen, May 08 2024

Status

approved