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A006146 Sums of prime divisors of Ruth-Aaron numbers (A006145). 4
5, 5, 7, 18, 15, 20, 44, 46, 29, 31, 50, 30, 20, 34, 75, 162, 146, 46, 14, 113, 53, 66, 333, 36, 514, 318, 43, 193, 279, 418, 30, 121, 55, 485, 200, 136, 77, 37, 211, 587 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

John L. Drost, Ruth/Aaron Pairs, J. Recreational Math. 28 (No. 2), 120-122.

Science, vol. 275, p. 759, 1997.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

G. Kreweras and Y. Poupard, Sur les partitions en paires d'un ensemble fini totalement ordonné, Publications de l'Institut de Statistique de l'Université de Paris, 23 (1978), 57-74. (Annotated scanned copy)

Ivars Peterson, Playing with Ruth-Aaron pairs

Ivars Peterson's MathTrek, Playing with Ruth-Aaron Pairs [In the internet archive]

Eric Weisstein's World of Mathematics, Ruth-Aaron Pair

FORMULA

a(n) = A008472(A006145(n)) = A008472(A006145(n) + 1). - Amiram Eldar, Nov 24 2019

MAPLE

with(numtheory): for n from 1 to 10000 do t0 := 0; t1 := factorset(n);

for j from 1 to nops(t1) do t0 := t0+t1[ j ]; od: s[ n ] := t0; od:

for n from 1 to 9999 do if s[ n ] = s[ n+1 ] then lprint(n, s[ n ]); fi; od:

CROSSREFS

Cf. A006145, A008472, A039752, A039753, A039703, A054378.

Sequence in context: A088047 A109257 A088048 * A284129 A077956 A077977

Adjacent sequences:  A006143 A006144 A006145 * A006147 A006148 A006149

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified February 23 15:34 EST 2020. Contains 332167 sequences. (Running on oeis4.)