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A116459 Numbers n such that the minimal length of the corresponding shortest addition chain A003313(n)=A003313(3*n). 8
171, 342, 427, 683, 684, 854, 855, 1111, 1195, 1366, 1367, 1368, 1451, 1707, 1708, 1710, 2390, 2732, 2734, 2736, 2902, 3414, 3415, 3416, 3420, 3755, 4203, 4271, 4780, 4781, 5463, 5464, 5468, 5472, 5483, 5803, 5804, 6319, 6331, 6383, 6491, 6827, 6828 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Hugo Pfoertner, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3)=427 because both 427 and 1281=3*427 have associated shortest addition chains of length 12: [1,2,4,8,16,17,34,68,136,137,145,290,427] and [1,2,4,5,10,20,40,80,160,320,640,1280]. This is the third occurrence of such a pair. The first two are (171,513) and (342,1026).

CROSSREFS

Cf. A115016, A003313 [l(k)], A086878 [l(k)=l(2*k)], A261986 [l(k)=l(4*k)], A116460 [l(k)=l(5*k], A116461 [l(k)=l(6*k)], A116462 [l(k)=l(7*k)], A116463 [l(k)=l(9*k], A117151 [l(k)=l(10*k)].

Sequence in context: A183996 A062907 A266315 * A185610 A185837 A016057

Adjacent sequences:  A116456 A116457 A116458 * A116460 A116461 A116462

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Mar 07 2006

STATUS

approved

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Last modified March 23 14:17 EDT 2019. Contains 321431 sequences. (Running on oeis4.)