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A277848 Index at which n occurs in A217727, or 0 if there is no such index. 2
1, 7, 2, 5, 18, 21, 11, 8, 28, 35, 46, 74, 54, 25, 3, 129, 32, 39, 78, 58, 133, 43, 62, 6, 95, 91, 152, 171, 87, 71, 190, 16, 148, 328, 19, 181, 167, 51, 227, 405, 618, 355, 344, 254, 440, 83, 926, 22, 67, 277, 100, 157, 1400, 195, 333, 186, 1144, 232, 259, 445, 282, 105, 12, 237, 110, 115, 388, 211, 468, 383, 492, 144, 594, 307, 366, 206, 126, 533, 324, 9, 463, 642 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

It is conjectured that all integers >= 2 appear in A217727.

LINKS

Table of n, a(n) for n=2..83.

PROG

(PARI) A277848(n, a=2, u=[])={for(i=1, 9e9, a==n&&return(i); u=setunion(u, [a]); while(#u>1&&u[2]==u[1]+1, u=u[^1]); my(t=log(a)\1); a=if(t>u[1]&&!setsearch(u, t), t, a^2))} \\ This code computes ("for each n") the sequence A217727 up to the index where n occurs.

(PARI) A277848_vec(N, a=2, u=[], v=vector(N))={my(i=1, t); until(u[1]>N, a<=N&&v[a]=i; u=setunion(u, [a]); while(#u>1&&u[2]==u[1]+1, u=u[^1]); i++; a=if((t=log(a)\1)>u[1]&&!setsearch(u, t), t, a^2)); v[^1]} \\ This is more efficient to compute a whole range a(1..N).

CROSSREFS

Cf. A217727, A114183.

Sequence in context: A006577 A280234 A073652 * A248285 A117029 A128475

Adjacent sequences:  A277845 A277846 A277847 * A277849 A277850 A277851

KEYWORD

nonn

AUTHOR

M. F. Hasler, Nov 20 2016

STATUS

approved

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Last modified September 23 13:55 EDT 2017. Contains 292358 sequences.