A246349 - OEIS

A246349

Positions of records in A246272.

1, 2, 6, 10, 30, 42, 210, 330, 462, 2310, 6090, 30030, 66990, 94710, 434910, 651630, 1292646, 1610070, 2478630, 2497110, 2916690, 13220130, 20930910, 52582530, 60690630

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

All terms are squarefree. (See the comments in A246272).

From 2 onward they factorize as: 2, 2*3, 2*5, 2*3*5, 2*3*7, 2*3*5*7, 2*3*5*11, 2*3*7*11, 2*3*5*7*11, 2*3*5*7*29, 2*3*5*7*11*13, 2*3*5*7*11*29, 2*3*5*7*11*41, 2*3*5*7*19*109, 2*3*5*7*29*107, 2*3*17*19*23*29, 2*3*5*7*11*17*41, 2*3*5*7*11*29*37, 2*3*5*7*11*23*47, 2*3*5*7*17*19*43, 2*3*5*7*11*59*97, 2*3*5*7*11*13*17*41, 2*3*5*7*11*13*17*103, 2*3*5*7*11*13*43*47, ...

LINKS

Table of n, a(n) for n=1..25.

PROG

(PARI)

default(primelimit, 2^22)

A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ Using code of Michel Marcus

A065338(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = (f[i, 1]%4)); factorback(f);

A246272(n) = {my(i); i=0; while((A065338(n)!=1), i++; n = A003961(n)); i};

\\ Compute the b-files for both the positions of records (A246349) and their values (A246350) at the same time:

prevmax = -1; i = 0; for(n=1, 60690630, if((k=A246272(n)) > prevmax, prevmax = k; i++; write("b246349.txt", i, " ", n); write("b246350.txt", i, " ", k)));

(Scheme, with Antti Karttunen's IntSeq-library)

(define A246349 (RECORD-POS 1 1 A246272))

CROSSREFS

A246350 gives the corresponding record values.

Cf. A246272.

Sequence in context: A079855 A048692 A019095 * A026117 A283909 A107385

Adjacent sequences: A246346 A246347 A246348 * A246350 A246351 A246352

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 23 2014

STATUS

approved