A374479 - OEIS

A374479

Lexicographically earliest infinite sequence such that a(i) = a(j) => A001065(i) = A001065(j) and A343223(i) = A343223(j), for all i, j >= 1.

1, 2, 2, 3, 2, 4, 2, 5, 6, 7, 2, 8, 2, 9, 10, 11, 2, 12, 2, 13, 14, 15, 2, 16, 17, 18, 19, 20, 2, 21, 2, 22, 11, 23, 19, 24, 2, 13, 25, 26, 2, 27, 2, 28, 29, 30, 2, 31, 7, 32, 33, 34, 2, 35, 25, 36, 37, 38, 2, 39, 2, 40, 41, 42, 43, 44, 2, 45, 46, 47, 2, 48, 2, 49, 50, 51, 52, 53, 2, 54, 55, 56, 2, 57, 37, 58, 59, 60, 2, 61, 12, 62, 63, 26, 64, 65, 2, 66, 67

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OFFSET

1,2

COMMENTS

Restricted growth sequence transform of the ordered pair [A001065(n), A343223(n)].

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to sigma(n)

PROG

(PARI)

up_to = 65537;

rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om, invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om, invec[i], i); outvec[i] = u; u++ )); outvec; };

A001065(n) = (sigma(n)-n);

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));

A342926(n) = (A003415(sigma(n))-n);

A343223(n) = gcd(A003415(n), A342926(n));

Aux374479(n) = [A001065(n), A343223(n)];

v374479 = rgs_transform(vector(up_to, n, Aux374479(n)));

A374479(n) = v374479[n];

CROSSREFS

Cf. A000203, A001065, A342926, A343223.

Cf. also A305800, A374480.

Sequence in context: A305793 A300245 A346488 * A300231 A351030 A329381

Adjacent sequences: A374476 A374477 A374478 * A374480 A374481 A374482

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 07 2024

STATUS

approved