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A341511 Triangular array T(n,k) = A005940(1+A156552(n)+A156552(k)), read by rows, with n >= 1, 1 <= k <= n. 2
1, 2, 3, 3, 4, 5, 4, 5, 6, 9, 5, 6, 9, 8, 7, 6, 9, 8, 7, 10, 15, 7, 10, 15, 12, 25, 18, 11, 8, 7, 10, 15, 12, 25, 16, 27, 9, 8, 7, 10, 15, 12, 27, 18, 25, 10, 15, 12, 25, 18, 27, 14, 11, 16, 21, 11, 14, 21, 20, 35, 30, 49, 24, 45, 50, 13, 12, 25, 18, 27, 16, 11, 20, 21, 14, 35, 36, 45, 13, 22, 33, 28, 55, 42, 77, 40, 63, 70, 121, 60, 17 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
A341510 is the main entry for this dyadic function. See comments there.
LINKS
FORMULA
T(n, k) = A341510(n, k).
EXAMPLE
The triangle begins as:
1,
2, 3,
3, 4, 5,
4, 5, 6, 9,
5, 6, 9, 8, 7,
6, 9, 8, 7, 10, 15,
7, 10, 15, 12, 25, 18, 11,
8, 7, 10, 15, 12, 25, 16, 27,
9, 8, 7, 10, 15, 12, 27, 18, 25,
etc.
PROG
(PARI)
up_to = 105;
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), 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 };
A341510sq(n, k) = A005940(1+A156552(n)+A156552(k));
A341511list(up_to) = { my(v = vector(up_to), i=0); for(n=1, oo, for(k=1, n, i++; if(i > #v, return(v)); v[i] = A341510sq(n, k))); (v); };
v341511 = A341511list(up_to);
A341511(n) = v341511[n];
CROSSREFS
The lower triangular region of A341510 read by rows.
Cf. A000027 (the left edge), A003961 (the right edge).
Sequence in context: A361261 A120244 A094727 * A089308 A305579 A321440
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Feb 15 2021
STATUS
approved

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Last modified March 29 10:22 EDT 2024. Contains 371268 sequences. (Running on oeis4.)