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A088365 Local maxima of A053707 (first differences of A025475, powers of a prime but not prime). 2
4, 9, 17, 40, 74, 54, 151, 120, 307, 312, 199, 408, 356, 424, 912, 1032, 1217, 840, 1872, 423, 1608, 2518, 1588, 1920, 1230, 2112, 3713, 1560, 5208, 2832, 3952, 2872, 3192, 3288, 3432, 8400, 5738, 4080, 4272, 4512, 6288, 8280, 8520, 5232, 5352, 3672, 8892 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A053707(k) for k = 1 is a term iff A053707(k) >= A053707(k+1); A053707(k) for k > 1 is a term iff A053707(k-1) < A053707(k) and A053707(k) >= A053707(k+1).

A088366 gives the corresponding indices. Local minima of A053707 are in A088363.

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

The first six terms of A053707 are 3,4,1,7,9,2, hence A053707(2) = 4 is the first and A053707(5) = 9 is the second local maximum of A053707.

PROG

(PARI) {m=1; k=0; for(n=2, 250000, if(matsize(factor(n))[1]==1&&factor(n)[1, 2]>1, d=n-m; if((k<2||b<c)&&(!k<1&&d<=c), print1(c, ", ")); k++; m=n; b=c; c=d))}

CROSSREFS

Cf. A025475, A053707, A088366, A088363.

Sequence in context: A130785 A226310 A008236 * A139468 A127081 A162719

Adjacent sequences:  A088362 A088363 A088364 * A088366 A088367 A088368

KEYWORD

nonn

AUTHOR

Klaus Brockhaus, Sep 27 2003

STATUS

approved

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Last modified August 12 23:52 EDT 2022. Contains 356077 sequences. (Running on oeis4.)