login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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
1, 2, 4, 64, 352, 3531872, 992498752 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 17 03:42 EDT 2021. Contains 347478 sequences. (Running on oeis4.)