The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A351962 Square array A(n,k) = A156552(lcm(A005940(1+n), A005940(1+k))), read by antidiagonals. 4
0, 1, 1, 2, 1, 2, 3, 5, 5, 3, 4, 3, 2, 3, 4, 5, 9, 11, 11, 9, 5, 6, 5, 10, 3, 10, 5, 6, 7, 13, 5, 19, 19, 5, 13, 7, 8, 7, 6, 11, 4, 11, 6, 7, 8, 9, 17, 23, 27, 21, 21, 27, 23, 17, 9, 10, 9, 18, 7, 22, 5, 22, 7, 18, 9, 10, 11, 21, 21, 35, 39, 13, 13, 39, 35, 21, 21, 11, 12, 11, 10, 19, 20, 23, 6, 23, 20, 19, 10, 11, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
The indices run as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), etc. The array is symmetric.
LINKS
EXAMPLE
The top left corner of the array:
n=0 1 2 3 4 5 6 7 8 9 10 11 12
-----|-----------------------------------------------------------
k= 0 | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
1 | 1, 1, 5, 3, 9, 5, 13, 7, 17, 9, 21, 11, 25,
2 | 2, 5, 2, 11, 10, 5, 6, 23, 18, 21, 10, 11, 26,
3 | 3, 3, 11, 3, 19, 11, 27, 7, 35, 19, 43, 11, 51,
4 | 4, 9, 10, 19, 4, 21, 22, 39, 20, 9, 10, 43, 12,
5 | 5, 5, 5, 11, 21, 5, 13, 23, 37, 21, 21, 11, 53,
6 | 6, 13, 6, 27, 22, 13, 6, 55, 38, 45, 22, 27, 54,
7 | 7, 7, 23, 7, 39, 23, 55, 7, 71, 39, 87, 23, 103,
8 | 8, 17, 18, 35, 20, 37, 38, 71, 8, 41, 42, 75, 44,
9 | 9, 9, 21, 19, 9, 21, 45, 39, 41, 9, 21, 43, 25,
10 | 10, 21, 10, 43, 10, 21, 22, 87, 42, 21, 10, 43, 26,
11 | 11, 11, 11, 11, 43, 11, 27, 23, 75, 43, 43, 11, 107,
12 | 12, 25, 26, 51, 12, 53, 54, 103, 44, 25, 26, 107, 12,
13 | 13, 13, 13, 27, 45, 13, 13, 55, 77, 45, 45, 27, 109,
14 | 14, 29, 14, 59, 46, 29, 14, 119, 78, 93, 46, 59, 110,
15 | 15, 15, 47, 15, 79, 47, 111, 15, 143, 79, 175, 47, 207,
16 | 16, 33, 34, 67, 36, 69, 70, 135, 40, 73, 74, 139, 76,
PROG
(PARI)
up_to = 104;
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res };
A351962sq(n, k) = A156552(lcm(A005940(1+n), A005940(1+k)));
A351962list(up_to) = { my(v = vector(1+up_to), i=0); for(a=0, oo, for(col=0, a, i++; if(i > #v, return(v)); v[i] = A351962sq(col, (a-(col))))); (v); };
v351962 = A351962list(up_to);
A351962(n) = v351962[1+n];
CROSSREFS
Cf. A001477 (main diagonal).
Cf. also A341520, A351960, A351961.
Sequence in context: A363226 A075758 A125596 * A253026 A341145 A204994
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Feb 26 2022
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 28 00:20 EDT 2024. Contains 372900 sequences. (Running on oeis4.)