A088079 Diagonal T(n,n) of the triangle T(n,k), n>=0, 0<=k<=n, in which row n contains n+1 consecutive integers T(n,k+1)=T(n,k)+1 such that T(n,k) is divisible by a k-th power.

1, 2, 4, 64, 352, 3531872, 992498752

Offset

0,2

Links

Table of n, a(n) for n=0..6.

Example

In row n=4, T(4,4)=352 is divisible by 2^4, T(4,3)=351 is divisible by 3^3, T(4,2)= 350 is divisible by 5^2 and T(4,1)=349 is divisible by 349^1 and T(4,0) is divisible by any x^0.
Table starts
1;
1,2;
2,3,4;
61,62,63,64;
348,349,350,351,352;

Prog

(PARI)
okdivs(n, k) = {fordiv(n, d, if (d != 1 && ispower(d, k), return (1))); return (0); }
oknbrs(n, i) = {my(k); forstep (k=n, 2, -1, if (! okdivs(i+k, k), return (0)); ); return (i); }
row(n) = {if (n == 0, print(1); return; ); my(i = 1); while (1, if (oknbrs(n, i), for (k=0, n, print1(i+k, ", ")); print(); return; ); i++; ); }
tabl(nn) = {for (n=0, nn, row(n); ); }
\\ Michel Marcus, May 14 2013

Crossrefs

Cf. A088078.

Sequence in context: A124592 A275203 A232444 * A118993 A219735 A279969

Adjacent sequences: A088076 A088077 A088078 * A088080 A088081 A088082

Keyword

more,nonn

Author

Amarnath Murthy, Sep 22 2003

Extensions

a(5) from R. J. Mathar, Jul 19 2007

a(6) from Sean A. Irvine, Feb 17 2011

Status

approved