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A086284 Number of prime squares with maximum integer n (see comment for definition). 0
1, 3, 5, 11, 14, 21, 29, 37, 56, 88, 110, 145, 171, 197, 241, 302, 347, 392, 438, 484, 555, 650, 717, 806, 916, 1026, 1180, 1334, 1451, 1600, 1765, 1930, 2101, 2315, 2539, 2816, 3108, 3400, 3702, 4063 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A prime square is constructed by drawing a square and placing a positive integer at each corner. All adjacent corners must sum to a prime. The maximum integer is the largest integer that may be used.

LINKS

Table of n, a(n) for n=1..40.

EXAMPLE

a(4)=11 since we have the 2 X 2 squares:

11 21 21 32 32 41 43 43 43 43 41

11 11 12 21 23 14 14 34 12 32 12

PROG

(PARI) { ps(n)=local(s); s=2; forstep (i1=1, n, 2, forstep (i2=2, n, 2, forstep (i3=i1, n, 2, forstep (i4=i2, n, 2, if (isprime(i1+i2) && isprime(i2+i3) && isprime(i3+i4) && isprime(i4+i1), s++))))); if (n==1, s=1); if (n==2, s=3); s } for (i=1, 40, print1(ps(i)", "))

CROSSREFS

Sequence in context: A058595 A154773 A176658 * A136500 A024897 A048702

Adjacent sequences:  A086281 A086282 A086283 * A086285 A086286 A086287

KEYWORD

nonn

AUTHOR

Jon Perry, Aug 28 2003

STATUS

approved

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Last modified February 21 06:25 EST 2018. Contains 299390 sequences. (Running on oeis4.)