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A130870 Palindromic primes with squareful neighbors. 1
151, 727, 919, 10601, 14741, 15451, 15551, 16361, 16561, 19891, 30403, 31013, 33533, 34543, 35153, 39293, 70507, 71317, 72227, 73637, 75557, 78787, 79397, 93139, 94049, 94349, 94649, 94849, 94949, 95959, 97579, 1022201, 1055501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sequence is the intersection of A075432 and A002385. - Chai Wah Wu, Jun 09 2015

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..1446

MATHEMATICA

squarefulQ[n_] := Last[Sort[Transpose[FactorInteger[n]][[2]]]] > 1; palindromeQ[n_] := Reverse[IntegerDigits[n]] == IntegerDigits[n]; Select[Range[3, 2000000], palindromeQ[ # ] && squarefulQ[ # - 1] && squarefulQ[ # + 1] && PrimeQ[ # ] &]

PROG

(Python)

from sympy import isprime, factorint

def palgen10odd(l): # generator of palindromes in base 10 of odd length <= 2*l

....if l > 0:

........yield 0

........for x in range(1, l+1):

............for y in range(10**(x-1), 10**x):

................s = str(y)

................yield int(s+s[-2::-1])

A130870_list = []

for i in palgen10odd(5):

....if i > 2 and isprime(i) and max(factorint(i-1).values()) > 1 and max(factorint(i+1).values()) > 1:

........A130870_list.append(i) # Chai Wah Wu, Jun 09 2015

CROSSREFS

Cf. Palindromic subsequence of A075432 - Primes with no squarefree neighbors.

Sequence in context: A164622 A176138 A139640 * A211555 A143012 A250375

Adjacent sequences:  A130867 A130868 A130869 * A130871 A130872 A130873

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova, Jul 24 2007

STATUS

approved

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Last modified August 21 17:33 EDT 2017. Contains 290891 sequences.